QA 364 1911 , Smith- The teaching of Southern Branch' of the University of California Los Angeles Form L-l This book is DUE on the last date stamped below m JUL FEB 29 MAR 5 / 23^2* n 15 OCT 2 1 Form L-9-2w-7,'22 OCT 6 1931 FEB 1? 1932 By DAVID EUGENE SMITH, LL.D. Professor of Mathematics in Teachers College, Columbia University -2. 2. & d Reprinted, with revisions and additions, from the Teachers College Record, Vol. X, No. i, January, 1909 FOURTH EDITION PUBLISHED BY , doliunbta NEW YORK CITY 1911 922 Copyright, 1909, by Teachers College, Columbia University PKESS OF THE BRANDOW FEINTING COMPANY ALBANT, N. Y. A crp- PREFACE The Teachers College Record for March, 1903, contained an article on Mathematics in the Elementary School by the author's colleague Professor McMurry and himself. This number, how- ever, has long since been out of print, and as a result of this fact it was thought best in the autumn of 1908 to prepare a new number of the Record on The Teaching of Arithmetic. This was done by the author, and the article appeared in January, 1909. Although it was thought that the unusually large edition was sufficient for all demands for some years to come, it was ex- hausted within a few weeks, and it became necessary to print the article in book form. In spite of the fact that the work was originally written in a popular style, to the end that it might be read by those who have no more interest in mathematics than in the various other subjects of the curriculum, it has been thought best to make but a few changes in arranging for its publication in the present form. Intended as it is for those who are teaching or supervising the work in arithmetic in the elemen- tary schools, it would hardly serve its purpose if it departed widely from the practical and entered the domain of pure theory. As between influencing the few or the many on a topic of such general interest it has been thought better to adopt the latter course, and to prepare a book that might have place in educational reading circles generally and serve as a basis for the work in the class-room for the training of teachers. TABLE OF CONTENTS CHAPTER I. ^ The History of the Subject 5 CHAPTER II. The Reasons for Teaching Arithmetic 8 CHAPTER III^ What Arithmetic should include 12 CHAPTER IV. The Nature of the Problems 15 CHAPTER V. The Arrangement of Material 19 CHAPTER VI. Method 22 CHAPTER VII. Mental or Oral Arithmetic 26 CHAPTER VIII. Written Arithmetic 30 CHAPTER IX. Children's Analyses 35 CHAPTER X. Interest and Effort 39 CHAPTER XI. Improvements in the Technique of Arithmetic 42 CHAPTER XII. Certain Great Principles of Teaching Arithmetic. . 52 CHAPTER XIII. General Subjects for Experiment 55 CHAPTER XIV. Details for Experiment 65 CHAPTER XV. The Work of the First School Year 76 CHAPTER XVI. The Work of the Second School Year 85 CHAPTER XVII. The Work of the Third School Year 91 CHAPTER XVIII. The Work of the Fourth School Year 98 CHAPTER XIX. The Work of the Fifth School Year 102 CHAPTER XX. The Work of the Sixth School Year 107 CHAPTER XXL The Work of the Seventh School Year m CHAPTER XXII. The Work of the Eighth School Year 115 THE TEACHING OF ARITHMETIC CHAPTER I S/t>. 7- 1 THE HISTORY OF THE SUBJECT 2. 2.2. 8 etc.)? If counting forward is an aid to addition, how far can counting backward be an aid to subtraction? How far is real counting backward (by sheer act of consecutive memory) of valid social use? (4) How far shall the three processes of (i) oral counting, (2) reading of numbers, and (3) writing of numbers, be parallel in the first year of formal arithmetic teaching? Should counting precede reading, and reading precede writing of numbers ? How far are they dependent upon each other? In relation to accom- plishment in any one of these, when should the teaching of the other begin? (5) Why do young children who know their numbers up to twenty write 16 correctly at first, and later, when they are sup- posed to know their numbers to 100, write 16 as 61 ? Would further and special drill on certain numbers of the series have prevented this error? Which numbers require this special care? Why do children sometimes say " five-teen ? " (6) In teaching children to read and write numbers, how far is it useful and how far is it confusing to have them know the place names (unit of units, tens of units, hundreds of units, etc.) ? Should such a classification be given to the child finally, or not at all ? Is the so-called method of " group reading " superior to the " place " method ? To the method of direct memorization ? In the " group " method a child reads and writes all his numbers as he would numbers of three figures or less, naming them from the commas which mark off the groups of three, as in 34,026, " 34 " = " thirty-four," " , " = " thousand," " 026 " = " twenty-six." What are the special errors which are peculiar to the " place " method ? What are the special errors peculiar to the " group " method ? (7) Are all numbers of from four to six places equally easy to read and write? If not, what are the types representing gradations of difficulty? Taking the following types: 68 The Teaching of Arithmetic 4,000 In which are errors most frequent? When these 80,000 same figures appear, not in " thousands place " but 13,000 in " units place," would the order of difficulty 257,000 be the same or different? As in 1,000 900,000 i, 2 57 120,000 i,9 304,000 i, 1 20 1,304 1,013 1,004 i, 080? It will be noted that there are seven types in the first list and eight in the second, due to the introduction of ,000. Note also that 4, becomes ,004 in the second list, and passes from the easiest to next to the most difficult. Are such distinctions characteristic of children's experiences with numbers? How does some provision for equalizing drill in all types of numbers minimize the unequal distribution of errors, as opposed to the hit-and-miss methods of drilling from personal lists made up by the teacher as he needs them? According to the types enumerated above as a result of the investigation of thousands of children's papers, would there not be 56 (7X8 = 56) drill types for thousands, and 448 (7X8X8 = 448) for numbers in millions place? (8) It is generally said that there are forty-five fundamental combinations which are the basis of all work in addition. What are the fundamental facts that are required as basic and which, once learned, may be applied in new forms and situations over and over again? There are ten numbers, from o up to 9. Each of these may be combined with itself and the nine others, thus making 100 combi- nations, from + = up to 9 + 9 = 18. The 19 zero com- binations are left out, leaving 81 combinations. Of the 81 remaining, 36 are reverses (2 + 7 = 9 ' 1S a reverse of 7 + 2 = 9). Omitting these there are 45 combinations left as fundamental. Is this procedure correct? (9) How far does the learning of 7 + 2 = 9 also guarantee the acquiring of its reverse, 2 + 7 = 9? Will the second be known without further drill? With how many less repetitions Details for Experiment 69 will it be learned because the other combination is mastered? Will the two combinations mentioned be learned with fewer repe- titions when they are constantly learned together, as opposed to being learned as separate individual combinations the relation of which is not specially kept in mind? (10) Is there a justification for saying that the zero combina- tions (0 + 3 = 3) mav b e omitted as not being basic? The contention is that they never occur in single combination. No one says, " I have nothing and three, and adding them I have three." In such a situation we merely count what we have, we do not add our count to what we do not have, for we are not conscious of the latter numerically. But may not the zero combinations be necessary for their later application in column addition ? 6 + 3 = 9 is used as 16 + 3= 19 and + 4 = 4 is used as 10 + 4 = 14. Is it true that all zeros in column addition are ignored? In four conceivable cases, o + 4 = 4 4 + 0= 4 10 + 4= 14 14 + o = 14 where the zero is found in column addition, it may be said that in three the zero is treated with one attitude ; it is ignored. In the case of 10 + 4=14 the zero is treated as part of quantity, and must be learned. Must not the child know all the applied zero combinations from 10+2=12 up to 10 + 9=19, and must not these eight combi- nations be provided somewhere in the child's instruction ? Which then is the most economical and efficient way of teaching the zero combinations mentioned ? To teach them as + 4 = 4 an d then apply as 10 + 4= 14, or to teach as 10 + 4= 14 from the very beginning? Experimentation ought to reveal the relative value of the two methods. It ought to reveal the difference between making some provision for them and making no formal provision. (n) In the list of forty-five fundamental combinations, the zero combinations were left out (when some should probably have been left in) and the combinations with one (6+1=7) were left in. Should they also have been left in? As no one adds o to a number in a single combination in actual life, it might be asked if we ever add one? We really count one more, not add. When we have 6 and i more, do we not count 6, 7, nor add 6 + I 70 The Teaching of Arithmetic = 7. Counting is a more fundamental habit than adding, and it is contended that when i is met in any column, the mind really climbs the scale i, it does not group it as where 3 is met. If this is so the children being able to count serially already, need not learn one as an addition. This would omit 17 combinations. Experimentation would show how far children taught the com- binations with i were superior in column addition where I's occurred, to children who had not had any training in com- binations with ones. (12) In actual instruction many teachers do not drill one type of combination any more than another. The additional drill comes later when the child fails or gets confused. Additional drill is used as cure rather than as preven- tion of mistake. Of the four types given, 4 + 5 = 9 which is the easiest for children ? Which 3 + 7 = 10 the hardest? If errors are more frequent in 9 + 6=15 some types than in others, is this due to 10 + 8 = 18 the innate difficulty of certain types or to the methods of teaching them? Do chil- dren add from large to small numbers (9 + 5) more readily than from small to large numbers (5+9 -14)? (13) Some courses of study require that a combination once learned (5 + 7=12) be applied immediately to the higher decades (15 + 7 = 22, 25 + 7 = 32, etc.). How much superior in column addition is a class thus trained to one not so trained ? Is it necessary to apply all combinations learned in this way? May it not be that the general idea of application is soon acquired with the first few combinations and that special drill is not required thereafter? Are there certain combinations where special drill must be insured always (5 +6 = eleven, 15 + 6 = twenty-one) because the sound regularity is interfered with ? Or may a strictly written presentation do away with the necessity of special drill even here? (14) Is there any increase of efficiency in drilling on combina- tions in columns as soon as possible? As soon as the com- binations that add up 7 are learned is there a special advantage in immediately giving the child such columns in application as the following: Details for Experiment 71 2 4 24 3 i 3i 2 2 22 7 7 77 (15) In some texts and courses of study the addition combina- tions are presented in the order of the sizes of the sums, thus 2+2 = 4, 2 + 3 = 5, etc. In others 6 the combinations are presented, regardless of the size 3 of the numbers involved, so as to immediately fit into 6 certain drill columns already prepared. Thus the an- 4 nexed column would require the following combina- tions (beginning from the bottom), 4 + 6=10, 19 + 3 = 3, an d 3 + 6 = 9. What is the relative worth of these two methods? (16) In column addition, where carrying is involved, some rationalize the process, and others teach it mechan- 23 ically as a mere bit of habituation. In the case 47 here given, some would add each column sepa- 36 rately, taking a second total of the partial sums. Others would merely " put down the six and add 1 6 one to the next column," writing down only the 9 complete sum. Which is superior, in that it will result in accurate and rapid column addition in 106 the shortest space of time? The preceding treatment of addition will suggest similar problems as more or less recurring in subtraction, e. g., whether there is any gain in teaching 5 3 = 2 immediately after learning that 5 2 = 3, etc. (17) Is there any advantage in the so-called "Austrian" method of subtraction by addition, over the method of subtracting through specially learned subtraction combinations? If so, how much considering that subtraction and addition 4 10 (i) mean different concrete situations, (2) + 6 6 use a different written algorism, (3) use the same oral form ("6 and 4 are 10"), and (4) 10 4 employ the same memorization (6 and 4 are 10) ? What extent of school energy is saved, if any? Is the method of subtraction from the next digit in the 72 The Teaching of Arithmetic top number superior or inferior to the method of adding to the next digit in the bottom number ? How is it when these methods are applied to the addition-method of subtraction? to the " old " subtraction-combination method ? (18) Do children make fewer errors when they are formally taught to make a preliminary inspec- 389 tion of subtraction examples before proceeding 421 to manipulate specific combinations? as when the number cannot be subtracted; as when the 345 answer is zero. (See the two examples here 345 given.) (19) Do children make fewer errors and manifest less con- fusion where they are formally taught to handle the zero diffi- culties prior to being confronted with them in column subtrac- tion? As in the type cases given below: (a) 867 (b) 867 (c) 867 (d) 870 467 400 32 650 400 467 835 220 Where borrowing from top? (e) 128 (f) 602 (g) 612 (h) 612 76 237 318 308 52 365 294 304 Where adding to bottom? (0 834 (j) 834 (k) 804 (1) 814 406 496 496 406 428 338 308 408 In subtraction, what preparation is needed in a command of zero combinations to perform the column subtraction? (Note each case given above.) Is there some general mode of handling these zeros that will not require a mastery of it in connection with each number it may be combined with? How does the above apply to the combinations with ones? Where a one is involved, is it merely counting downwards or backwards? Or is the subtraction of I exactly like the subtraction of 3 or 4 or any other number? (20) What are the basic combinations required to perform any given column subtraction? In what form may they be best Details for Experiment 73 mastered? Are zero subtractions (6 = 6) and subtractions with one (61 = 5) to be included or omitted? Are the re- verses to be taught as basic? (7 2 = 5 and 7 5 = 2.) Are subtraction combinations of varying difficulty? Which are the most difficult, as shown by children's errors? (21) Will children have less difficulty, with fewer ensuing errors, if they approach column subtraction through a series of graded types of difficulty? Consider in the following: (a) No borrowing. 1498 964 534 (b) Borrowing each time save the last. 8431 5987 2444 (c) Borrowing alternately. 8431 2917 5514 In what order should types (b) and (c) be given? How rapidly may a child advance from two or three figures to seven or eight? What new difficulties present themselves in such an extension of figures? (22) Are the first series of multiplication combinations best presented (i) by the use of objects grouped and counted, or (2) by the use of column addition? Or are these two methods best used as supplementary to each other? Are the combinations with zeros (6X0 = 0) and the combinations with ones (6 X i = 6) best taught in the tables, or later, in con- nection with their actual use in column multiplication? Is there a gain in teaching the reverses in connection with the com- binations to which they are related, exactly as with the addition combinations, thus 6X3=18 immediately after 3X6=18? What gradation of steps is most economical and efficient in proceeding from combinations to their application in column multiplication? Since partial products represent but stages in calculation do they need to be understood as to their placing, or 74 The Teaching of Arithmetic should their placing be taught as a mechanical process through habit formation? Is it economical to allow zeros to be recorded which later will be abandoned? as in multiplying by 206? What special drill on zero difficulties (and on the manipulation of ones) is required in connection with their handling in column multipli- cation? How can this be best provided? (24) Is there any need for division tables of combinations? May not the multiplication tables be used for division, precisely as the addition combinations are used for subtraction? For example, from " 3 2's are 6," may we not step to the case of 2)6? " How many 2's are 6? " "3 2 ? s are 6." Here the identification is through a common oral form of expression. Is there any need to show that a specific written form or algorism in multiplication is the equivalent of another one in division, since this is not done in subtraction by addition? (25) In column addition, column subtraction, and column multiplication the fundamental combination is generally obvious in the process of manipulation. Is the division combination equally obvious in long and short division? Does this require special treatment? (26) Will children do long and short divisions more efficiently if drill in division with a remainder (after 12-^-3 = 4, learning 13-4-3 = 4, with i remainder, and 14 -r- 3 = 4, with 2 remainder) is inserted between the learning of the combinations and their application to long and short divisions? Since the largest diffi- culties seem to occur in connection with long division, and since division by a one-figure divisor must precede division by a num- ber of two figures, shall division by a one-figure number be first taught in its complete form? Shall division by a one-figure number be abridged to " short division " before or after the development of division with a divisor of two figures? Does the distinction between partition and measuring have any relation whatsoever to skill in manipulation? What is the worth of the distinction in interpreting problems and applying calculations? (27) How many special types of zero difficulties need be antici- pated and carefully drilled upon before children are allowed to attack examples where zero difficulties are likely to confront them? Is there any special order in which these zero difficulties should be attacked for purposes of economical mastery? What Details for Experiment 75 special training in the handling of ones should be provided for, especially if the one combinations in the tables are omitted? (28) The above list deals entirely with investigations in teach- ing which are mainly psychological. There is another large series of investigations as to the materials required in the various courses of study. These are sociological. In such investigations one would make such inquiries as the following: What is the demand for square root in ordinary business occupations ? What types of fraction examples are called for frequently, and what infrequently? Which types of reasoning combinations are most used ? Do we " add and multiply '' within the same problem, more frequently than we " multiply and add ? " Upon such social investigations should the selection and the omission, the emphasis and the subordination of specific topics be determined. Then will our courses of study represent the highest social efficiency. BIBLIOGRAPHY: Teachers should consult, on this topic, Pro- fessor Suzzallo's work already cited. CHAPTER XV THE WORK OF THE FIRST SCHOOL YEAR 1 The first question that naturally arises in connection with the arithmetic of the first grade is as to whether or not the subject has any place there at all. For several years past there has been in this country a propaganda in favor of excluding it as a topic from the first grade and even from the second. Like all such efforts, the history of which is not generally known, the very novelty of the suggestion, to many teachers, is sufficient to create a following. It is well to consider briefly the reasons for and against such a suggestion, and to attempt to weigh these reasons fairly before attempting any decision. In favor of having no arithmetic as such in the first grade it is argued that the spirit of the kindergarten should extend farther, perhaps even through all of the primary grades ; that number work should come in wherever there is need for it, all learning being made attractive and natural, and education appearing to the child as a unit instead of being made up of scattered frag- ments. Such a theory has much to commend it, not only in the primary school but everywhere else. Opposed to it is the rather widespread idea that most kindergarten work is superficial in aim and unfortunate in result; that children who have had this training are wanting in even the little seriousness of purpose that they should have, that they have no power of application, that they have been " coddled " mentally into a state that requires constant amusement as the condition to doing anything. The dispassionate onlooker in this old controversy probably feels that there is truth in both lines of argument, and that mutual good has been the result. Ancient education was a dreary thing, and 1 It is impossible in the space allowed to enter very fully into details as to the work of the various grades. Teachers who desire such details may consult the author's Handbook to Arithmetics (Boston, 1905). All that can be done in this article is to give a brief survey of some of the most important topics relating to the various grades. 7 6 The Work of the First School Year 77 to the spirit of the kindergarten, although not to extreme Frobelism, we are indebted for the brighter spirit of the modern school. On the other hand, to make children self-reliant, inde- pendent in thinking, conscious of working for a purpose, demands more thought than seems to pervade the ordinary kindergarten. Now as to arithmetic in the first grade: Shall we leave it to the ordinary teacher to bring in incidentally such number work as he wishes, or shall we lay down a definite amount of work to be accomplished and assign a certain amount of time to it ? And in answering these questions, are we bearing in mind the average primary teacher throughout the whole country? Are we also bearing in mind that arithmetic was never taught to children just entering school until about a century ago, and that it was largely due to Pestalozzi's influence that the subject was ever placed in the first grade? When, therefore, we advocate having no arith- metic in the first grade, we are going back a hundred years or so, which may be all right, but which is not a new proposition by any means. Having thus laid a foundation for an answer to the question, it is proper to proceed dogmatically, leaving the final reply to the reader. Not to put arithmetic as a topic in the first grade is to make sure that it will not be seriously or systematically taught in nine-tenths of the schools of the country. The average teacher, not in the cities merely but throughout the country generally, will simply touch upon it in the most perfunctory way. Whatever of scientific statistics we have show that this is true, and that children so taught are not, when they enter the intermediate grades, as well prepared in arithmetic as those who have studied the subject as a topic from the first grade on. Furthermore, while it is true that the essential part of arith- metic can be taught in about three years, it cannot, for psycho- logical reasons, be as well retained if taught for only a short period. The individual needs prolonged experience with number facts to impress them thoroughly on the mind. We can, for example, teach the metric system in an hour to any one of fair intelligence, but for one to retain it requires long experience in its use. But more important than all else is the consideration of the child's tastes and needs. Has he such a taste for number as 78 The Teaching of Arithmetic shows him mentally capable of studying the subject at the age of six, and are his needs such as to make it advisable for him to do so ? There can be no doubt as to the answer. He takes as much delight in counting and in other simple number work in the first grade as in anything else that the school brings to him, and he makes quite as much use of it in his games, his " playing store," his simple purchases, his reading, and his understanding of the conversation of the home and the playground, as he does of anything else he learns. If we could be certain that in the incidental teaching that is so often advocated he would have these tastes and needs fully satisfied, then arithmetic as a topic might be omitted from the first or any other grade; but since we are pretty sure that this will not be accomplished in the average school, then it is our duty to advocate a definite allotment of time and of work to the subject in every grade from the first through the eighth. This being so, what should tnis allotment of work be? Of course there is no general answer for the whole country. In some schools there are many foreign born pupils who are unable to speak English when they enter and therefore the first year's work must be devoted largely to acquiring the language. In other schools the children come from homes where they have already been taught by governesses and are considerably advanced over the average. In general, however, the course here laid down may be considered a fair average for the ordinary American school. The Leading Mathematical Feature. The introduction to the addition table, this being at the same time the simplest and the most important operation in arithmetic. It is not advisable to use a text-book in this year, on account of the children's in- ability to read. Number Space. It has been found best both from the stand- point of mental ability and of needs of the children to set a different limit to the numbers used in counting and in the opera- tions. Children like to and need to count numbers that are larger than those used in operations. For reading and writing numbers, therefore, they may profitably go as far as 100, meeting these numbers in the paging of books, the numbering of houses, the playing of games, and the counting of various objects. For the The Work of the First School Year 79 operations, however, it is sufficient if they go as far as 12. Indeed, 10 would make a good limit were it not for the fact that in measuring they so often use 12 inches. Addition. The addition tables should be learned at least as far as sums of 10 or 12. Some prefer to go as far as 9 + 4 = 13, but it is immaterial so long as the children know the table through 9's before the text-book is used, ordinarily the middle or the end of Grade II. Appropriate combinations for the first year may, therefore, be taken as follows: 123456789 I I I I I I I I I 23456789 10 12345678 22222222 3456789 10 1234567 3333333 4 5 6 7 8 9 10 123456 12345 444444 55555 56789 10 6789 10 1234 123 6666 777 7 8 9 10 8 9 10 12 I 88 9 9 10 10 This arrangement makes the sum the basis for selection. Many prefer, however, to proceed to master the table of I's, 2's, 8o The Teaching of Arithmetic 3's, and 4's, as mentioned above, thus giving the following com- binations : 123456789 10 iiiiiiiiii 1234 2222 1234 3333 4567 1234 4444 5678 It is not a matter of great importance which of these two arrangements is adopted in any given school system, at least so far as we are able to judge from any scientific investigations thus far made. The great thing is that the complete table shall be known to 10 + 10 by the end of the second year. Subtraction. Every fact learned in addition should, judging from general experience, carry with it the inverse subtraction case. That is, the question "3 + 2 equals what number ? " should carry with it the questions " 3 + what number equals 5 ? " and " 2 + what number equals 5 ? " or, if preferred, "5 3 equals what number?" and "5 2 equals what number?" Multiplication. Little attention should be given to this subject in the first grade. The idea that 2 + 2 + 2 may be spoken of as 3 times 2, and the incidental use of the word " times " in other simple number relations is desirable. Division. Since multiplication is not taken as a topic, its inverse (division) has no place, save as it appears in the fractions mentioned below. 6 7 8 9 IO ii 5 6 7 8 9 IO 2 2 2 2 2 2 7 8 9 IO II 12 5 6 7 8 9 IO 3 3 3 3 3 3 8 9 IO ii 12 13 5 6 7 8 9 IO 4 4 4 4 4 4 9 IO ii 12 13 14 The Work of the First School Year 81 Fractions. Children so often hear about the fractions l / 2 , %, and y 3 , that these ideas and forms may profitably be introduced at this time, although y 3 may be postponed to the next grade. The statement that half the class may go to the blackboard, the idea of % of a dollar, and that of l /$ of a yard, are all common in the first year. In the introduction of these ideas and symbols it is well to avoid extremes that will militate against the child's future progress, such as the extreme of the ratio method, for example. We should remember that a fraction, say y>, is com- monly used in three distinct ways, and, that it is our duty to see that, little by little, all these become familiar to the child. These ways are as follows: (i) l / 2 of a single object, the most natural idea of all, the breaking of an object into 2 equal parts; (2) ^ as large, as where a 6-inch stick is l / 2 as long as a foot rule, not half of it, but half as long as it is; this is essentially the ratio notion, and it is necessary to the child's stock of knowledge, but it is not necessary to make it hard by talking about ratios at this time; (3) */2 of a group of objects, as in the case of l /2 of ten children. Denominate Numbers. Children in this grade should learn the use of actual measures. They should know that 12 in. = i ft., 3 ft. = i yd., and should employ this knowledge in making meas- urements. They should know the cent, 5-cent piece, dime, and the dollar as 10 times (or even 100 cents), and should use toy money in playing store. They should know the pint and quart, and use these in measuring water or other convenient substance. Other terms such as pound, week, minute, mile, and gallon may be used incidentally, but they should not be, learned in tables, at present. Objects. It is important to use objects freely wherever they assist in understanding number relations, but it is equally impor- tant to abandon them as soon as they have served their purpose. The continued use of any particular set of objects (blocks, disks, measures, picture cards, etc.) is tiresome and narrowing. Pesta- lozzi was wiser than many of his successors when he used anything that came to hand to illustrate most of his number work. To continue to use objects after they have ceased to be necessary is like always encouraging a child to ride in a baby carriage. 82 The Teaching of Arithmetic Symbols. It cannot be too strongly impressed upon teachers that the symbols that children should visualize are those that they will need in practical calculation. Thus it is much better to drill upon the annexed forms than upon 6 9 9 6 + 3 = 9, 9 6 = 3, 9 3 = 6, since + 3 6 3 the latter are never used in calculation. , For ease in printing and writing, symbols 936 like 6 + 3 = 9 have their important place, but the eye should become accus- tomed to the perpendicular arrangement so as to catch number combinations as it must do when we come to actual addition. Technical Expressions. While it is proper to begin by reading 6 + 2 " six and two " and 8 6 " eight less six," the words " plus " and " minus " should soon enter into the vocabulary of the child as part of the technical language of the subject. It is proper to call a cat a " pussy " for a while, and a horse a " pony," but the time soon comes for " cat " and " horse," and so for the technical expressions in arithmetic. Nature of the Problems. In this grade problems of play, of the simplest home purchases, and of interesting measures should dominate. In general, for all grades, the oral problems should have a local color, relating to real things that the children know about. The building of a house near the school, the repairing of a street, the cost of school supplies these and hundreds of simi- lar ideas may properly suggest problems adaptable to every school year. It is the business of the text-book in the grades where it is used to furnish a large amount of suggestive written work, but it can never furnish all the oral work needed nor can it meet all local conditions. As a specimen of the early work in this grade the following oral exercise is submitted: 1 1. How many inches wide is the window pane? 2. How many feet long is your desk, and how many inches over? 3. How many feet and inches from the floor to the bottom of the blackboard? 1 These and other similar sets of problems used in this article are taken from other works of the author. The Work of the First School Year 83 4. Stepping as you usually do in walking, find how many paces in the length of the room. 5. How many paces wide do you think the room is? Pace the width and see if you are right. 6. How tall do you think you are? Measure. How many feet, and how many inches over? 7. How many inches from the lower left-hand corner of this page to the upper right-hand corner? 8. How wide do you think the door is? Measure. How many feet, and how many inches over? Such problems suggest measurements of genuine interest to the pupil, relating as they do to his immediate surroundings. They allow for the actual handling of the measures and the form- ing of reasonably accurate judgments concerning distances. Abstract Computation. It is a serious error to neglect abstract drill work in arithmetic. So far as scientific investigations have shown, pupils who have been trained chiefly in concrete problems to the exclusion of the abstract are not so well prepared as those in whose training these two phases of arithmetic are fairly balanced. Abstract work is quite as interesting as concrete; it is a game, and all the joy of the game element in education may be made to surround it. At the same time it is the most practical part of arithmetic, since most of the numerical problems we meet in life are simplicity itself so far as the reasoning goes; they offer difficulties only in the mechanical calculations involved, and constantly suggest to us our slowness and inaccuracy in the abstract work of adding, multiplying, and the like. In the first grade this work is largely but not wholly oral. Forms. It is expected that children in this grade will become familiar with the names of the common solids and polygons needed in their work. For example, square, rectangle, triangle, oblong, cube, sphere, cylinder, pyramid, prism, and similar forms should be handled and their names should be known. Paper cutting and folding is very helpful in the study of plane figures and in the work with fractions, although like any other device, it may be used to an extreme that is to be avoided. The Time Limit. Even in the first grade, and still more in the succeeding years, a time limit should be set on all number 84 The Teaching of Arithmetic work. The children should see how many questions they can individually, or as a class, or as half of the class, answer in a minute, or in some other period of time. Unless this is done, or some similar plan is adopted, the tendency to dawdle over the work will begin to crystallize into a habit, and computation will take much more time than necessary. It is also to be observed that, always within reasonable limits, rapid calculation contains less errors than very slow work. The reason is apparent; we concentrate our attention more completely, and other thoughts do not take our minds from the numerical work. BIBLIOGRAPHY : The author's Handbook to Arithmetics, p. 19 ; C. A. McMurry, Special Method in Arithmetic. On paper fold- ing consult Sundara Row's work, Geometric Paper Folding (Open Court Publishing Co.), illustrated by photographs taken by the author of the present work a few years ago. This work is suggestive, although not adapted to grade work. Consult also Wentworth-Smith, Stepping-Stones in Number, Boston, 1911. CHAPTER XVI THE WORK OF THE SECOND SCHOOL YEAR Whether or not arithmetic has a definite time allotment in the first grade, it usually has one in the second, although some teachers oppose it even there. The argument already advanced holds the more strongly here, especially as, in many schools, the child is quite prepared to use a text-book by the middle of this year. The Leading Mathematical Features. In schools of average advancement, where the question of language is not as serious as in some cities in the East, children in this grade may be expected to complete the addition tables and to learn the multi- plication tables to 10 X 5. Number Space. Children will now take an interest in count- ing to looo, first by units to 10, then by ID'S to 100, then com- pletely to 100, then by loo's to 1000, and finally completely to 1000. Their operations may also be anywhere within this space, although, of course, most of their results will involve only small numbers. In the Roman notation the limit may be set at XII, this sufficing for the reading of time and for the chapter num- bers of their books. Counting. Without going to an extreme in counting by various numbers where no definite purpose is served, there is a field in which counting is very advantageous. To count by 2's from 2 to 10 and from I to n has the pleasure of any rhythmic sequence and at the same time gives the addition table of 2's, and the counting by 2's from 2 to 20 gives the corresponding multi- plication table. Similarly, counting by 3's from 3 to 30 gives the multiplication table of 3's, while the further counting from i and 2 to 13 and 14 gives the different addition combinations. The exercise is interesting to children, and the knowledge secured in this way is more than one would at first think. Addition. The tables should be completed during this year, 85 86 The Teaching of Arithmetic including the sums of any two one-figure numbers. There are only 45 possible combinations of numbers below 10, viz.: I + I, 1+2, and so on to I + 9 ; 2+2, 2 + 3, and so on to 2 + 9 ; 3 + 3> 3 + 4> an ^ so on to 3 + 9 ; and similarly for the others to 9 + 9, besides the zero combinations referred to earlier in this paper. It is better, however, to continue the sums to include 10, a simple matter but one that is often helpful. The addition of numbers of two and even of three figures each may be taken during this year, but not more than five or six in a column should be used. Subtraction. Subtraction may be carried far enough to include numbers of three figures each. The method to be employed has already been discussed in Chapter XI. In both addition and subtraction there should be an effort to cultivate the habit of rapidity, although never to the exclusion of accuracy. The time limit on work, mentioned on page 83, should be employed in all written work. In general in both addition and subtraction the full form should be employed until it is thoroughly understood. For example, in adding 247, 376, and 85, a problem that must have been preceded by many simpler ones, it is well to use the first of the following forms until the reasons are understood, and then to adopt the second: 247 247 376 376 85 85 18 708 190 500 Likewise, if the addition or "Austrian " method is taken for subtraction, it is better to begin a problem like 852 476 in the full form, as follows: 852 = 800 +50 + 2 476 = 400 + 70 + 6 The difference between these is the same if we add 10 to each, and also 100 to each, and we add them as follows, so that we can easily subtract in each order: 800+ 150+ 12 500 +80+6 300 + 70 + 6 = 376 The Work of the Second School Year 87 After this is understood we may proceed to the ordinary arrangement. Multiplication. The multiplication tables may be learned this year as far as 10 X 5. Some schools go even as far as 10 X 10, and others find it better to postpone all of this work until the third grade. Products should be learned both ways, i. e., 5X6 and 6X5. There is a great advantage in reciting all tables aloud, and even in chorus, since this leads to a tongue and ear memory that powerfully aids the eye memory when the pupil needs to recall a number fact. Counting enables the tables to be developed in a rhythmic fashion that is pleasing to the ear, and shows multiplication by integers to be merely an abridged addi- tion, that is, that 3 + 3 + 3 + 3 is more briefly stated as 4X3. Division. The multiplication table should carry with it the division table. This need not be developed as a separate feature but may be treated as the inverse of the multiplication table exactly as subtraction is the inverse of addition. The fact that 4 X 6 = 24 should bring out the second direct fact that 6X4 = 24, and the two inverses, 24-1-6 = 4, and 24-^-4 = 6. These inverses may be introduced in a way that is analogous to that followed in subtraction. That is to say, after learning that 4 + 5 9 we ask, " What number added to 5 equals 9 ? " " What number added to 4 makes 9 ? " Similarly, after 4 X 5 = 20 we ask, " What number multiplied by 4 equals 20? " " What num- ber multiplied by 5 equals 20?" These may then be expressed as 20 *- 4 = 5, 20 -4- 5 = 4. In division in this grade we also have an illustration of the fact that the full form should precede the short one. A child more easily grasps the idea of 36 -f- 3 if he sees the first of these forms before he comes to use the second: 3)30 + 6 3)36 10+2 12 In the same way, when he comes to divide 36 by 2, it is better to begin with the first of the following forms : 2)20+16 2)36 10+8 18 Teachers will find it better to write the quotient below the dividend in short division, even though it is preferably written 88 The Teaching of Arithmetic above in the long process. There is no advantage in trying to change the habit of the world on such a small matter. 1 Fractions. Children know the meaning of l /2, %, and often of y$, on entering this grade. If y$ is not known it should be introduced and ^, Vc> Vs mav a ^ so ^e added to the list at this time, although many successful teachers prefer to postpone them until Grade III. The use of objective work is imperative, and it is better to take various simple materials than to confine one's self to elaborate fraction disks or other similar devices. Every school has cubes to work with, and the use of cubes, paper fold- ing, paper cutting, and the common measures is recommended as quite sufficient. Denominate Numbers. The denominations already learned in Grade I should be frequently used, and to them should be added the relation between the ounce and pound; the pint, quart, and gallon; the quart, peck, and bushel; the reading of time by the clock, and the current dates. The idea of square measure (in square inches) is introduced. All of this work should be done with the measures actually in hand so far as this is possible. A table of denominate numbers means very little unless accompanied by the real measures. This will be felt by any American grade teacher who teaches the metric system without the measures, and who tries to think of his weight in kilos, his height in centi- meters, and the distance to his home in kilometers. Symbols. It has already been said that symbols like +, , X, and -T- were invented for algebra and have only recently found place as symbols of operation in arithmetic. 2 The desire to employ them has led many teachers to use long chains of opera- tions that are never seen in practical life and which, while serving some purpose in oral work, are vicious as written exercises. For example, 2+4-^-2 + 5X6-^-3 + 3 is a kind of work that should never appear in the grades. Arithmetically it is easy enough, and the answer is 17, but there is no use in puzzling a child to remember which signs have the preference in such a chain. This is a small technicality of algebra, of which the impor- tance is much overrated even there, and it has no place in 1 See the author's Handbook, p. 27. 2 It is true that + and were first used in Widman's arithmetic of 1489, but not as symbols of operation. See my Kara Arithmetica. The Work of the Second School Year 89 the elementary school. With respect to the symbols 2 X $3 and $3X2 there is, however, a reasonable question, since there is good authority for each. Modern usage favors the former because we more naturally say " 2 times 3 dollars " $3 than " 3 dollars multiplied by 2," and it is better to 2 read from left to right as in an ordinary sentence. It should be repeated, however, that the forms which the $6 child needs to visualize are not these but the one he will meet in actual computation, as here shown. Objects. It is here repeated, as essential to a discussion of the work of the second grade, that objects are necessary in devel- oping certain number relations, but that they should be discarded as soon as the result is attained. Number facts must be memo- rized by every one, and objects may become harmful if used too often. Nature of the Problems. This matter begins to assume con- siderable importance in this grade, and it has been already dis- cussed in Chapter IV. It may be said in general, however, that several of our recent American arithmetics are making a serious effort to improve the applications of the subject, adapting them to the mental powers and to the environment of the pupils in- stead of offering obsolete material of no practical value and of little interest. Necessity for Systematic Reviews. It is proper at this time to call the attention of teachers to the matter of reviews, not those that naturally occur from time to time during the year, but those that should deeply concern every school at the close of one year and at the opening of the next one. Any one who has ever had much to do with the supervision of the grade work in arithmetic is struck by the general complaint that children are never pre- pared to enter any particular grade. Every teacher seems to feel that the preceding teacher has imposed a poorly equipped lot of children upon her own grade and that her problem is therefore hopeless. Now if this were only an occasional complaint the supervisor might well be worried, but he soon recognizes it as part of the tradition of the school, and pays little attention to it accordingly. What does it mean, however, and how should we remedy the evil if evil there be? If any teacher will himself learn, let us say, the logarithms of the first fifty integers, between September and February, how po The Teaching of Arithmetic many will he know in June? And if he knows them all in June how many will he remember at the end of the summer vacation ? And how will he feel, say about September 15, if some one suddenly asks him to give the logarithm of 37 to six decimal places, telling him, if he fails, that he must have been pretty poorly taught the year before ? Now this is a fair illustration of the mental position of a child with respect to the multiplication table when he enters Grade IV. Psychologically it would be strange if he could rapidly and accurately give every product demanded ; his brain cells have clogged up or got disarranged or gone through some similar transformation during his nine or ten weeks of careless play. What, therefore, is the teacher's duty? There are two things to do. First, at the close of each school year, in June, there should be a thorough and systematic review of those number facts and operations that are the funda- mental features of the year's work. The teacher ought to be satisfied that each child leaves the grade with such a mental equipment as shall leave no chance of fair criticism. His respon- sibility then ceases. Second, and even more important, at the opening of each school year, in September, there should again be a thorough and systematic review by the teacher in the next grade, of these same features. But this review should be con- ducted in the most sympathetic spirit. The teacher should be surprised if the children have not forgotten much rather than if they have failed to remember the facts perfectly. He should think of his own fifty logarithms, for example, and the review should be patiently and helpfully extended until the children's arithmetical brain-cells resume their former state. After this has been done in the spirit mentioned, and after the teacher has gone into the next higher grade for a day to see 'how his own pupils of the preceding year are standing the test, then he may be justified in complaining, but not before. It need hardly be mentioned that there are few more severe tests of the ingenuity and patience of a teacher than are found in these reviews. The " edge of interest " is already worn off in any review, and it requires all the tact a teacher possesses to maintain the enthusiasm of the pupils in such exercises. The result, how- ever, is well worth the effort, and the school system that carries out the plan will have less of complaint and more or sympathetic cooperation than would at first be thought possible. CHAPTER XVII THE WORK OF THE THIRD SCHOOL YEAR The Preparation. Since the text-book is placed in the hands of children during the latter part of the second school year or at the opening of the third, it becomes particularly important to have a systematic review of the work of Grades I and II at the beginning of this year. The text-books usually provide for this, and by their help these important things are accomplished: (i) The children's memories are refreshed as to the essential fea- tures of the preceding year's work, viz., the addition table, and the multiplication table as far as the course of study may require. (2) Children are " rounded up," brought to a certain somewhat uniform standard, so that all can begin the serious use of the text-book with approximately the same equipment. (3) The superior capacity or the defect of the individual has an opportu- nity to show itself early, allowing for such advancement or special attention as the case demands. In other words the " lock- step " can be broken without the usual delay. As to further argu- ment for this autumnal review the reader may refer back to Chapter XVI. The Leading Mathematical Features. In this year rapid written work is an important feature. The oral has predomi- nated until now, but in Grade III the operations involve larger numbers than before, and the child begins to acquire the habit of writing his computations. Multiplication extends to two- figure multipliers and long division is begun. The most useful tables of denominate numbers are completed. Number Space. It is usually considered sufficient if the child understands numbers to 10,000 in this grade, although he may be allowed to count by io,ooo's to 100,000 or even farther. Indeed, as soon as he understands numbers to 1,000 he rather enjoys showing his prowess by counting by i.ooo's and by writing large numbers. Counting always extends far beyond the needs of 92 The Teaching of Arithmetic computation a law that is true to-day and has been true in the historical development of all peoples. In the writing of Roman numerals there is no particular object in going beyond C in the first half-year, and M in the second half. It must be borne in mind that we use the Roman forms chiefly in chapter or section numbers, and less often in reading dates, so that all writing of very large numbers by this system in an obsolete practice and a waste of time. Indeed it is not strictly a Roman system any more, so much have we changed the numerals from their early forms. Counting. In this grade the counting of Grade II should be continued, including the 6's, 7's, S's, 9's, and lo's, as a basis for the multiplication tables and as a review of the addition combina- tions. There is no need of counting beyond certain definite limits, however. Thus in counting by 2's beginning with o, we have o, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20. This suffices for the multi- plication table of 2's and even the last half of this is merely a repetition of the first half with 10 added. The Decimal Point. It becomes necessary in this grade to write dollars and cents, and hence forms like $10.75, $ 2 5- IO > & n d $32.02 are given. It is not necessary nor even desirable that the children should know any of the theory of decimal fractions at this time. The decimal point should be looked upon by them simply as separating dollars and dimes, and it will give no trouble unless the teacher confuses the class by the ever-present danger of over-explaining. Forms. It is usual in Grade III to review the simple geo- metric forms already learned, such as the triangle, rectangle, cylinder, and sphere. Formal definitions are, however, undesir- able. The chief thing is that the child should use the names correctly. Some little paper-folding may well be introduced as a basis for simple square and cubic measure. Square and Cubic Measure. The ideas of area (square inches or square feet) and volume (cubic inches or cubic feet) may enter into the work of this grade, although some successful teachers prefer to introduce them in Grade IV, finishing this work in Grade V. If introduced here, they are of course treated objectively, usually with paper-folding, drawing, or inch cubes of wood. There is hardly any trouble with this work unless the teacher enlarges upon its difficulties. If there is accuracy of The Work of the Third School Year 93 language, spoken and written, from the beginning, this will con- tinue; but if the teacher allows expressions like " 3 inches times 3 inches equals 9 square inches," instead of " 3 times 3 square inches equals 9 square inches," there will be produced loose habits of thought and expression that will lead to great trouble. Devices for Fractions. It is still necessary in this grade to make a good deal of use of objective work in treating fractions, and to make the work largely oral dur- ing the first half year. There is also an 2 3 4 5 advantage in using columns of figures 2345 like those here shown. Here it is very 2345 easy to see that ^ of 8 is two 2's, or 4 ; 2 3 4 5 that y 4 of 12 is 3 ; that ^4 of 16 is three 4's or 12, and that l / 2 of 20 is the same 8 12 16 20 as V* of 2O > or two 5's, or 10. From the second arrangement it is easy to see 2 that 2 is y 2 of 4, y$ of 6, J4 * 8, and 2 2 Y B of 10; that 4 is ^ of 6, y 2 of 8; that 222 6 is 3/4 of 8 and 8 / 5 of 10, and so on. 2222 Devices of this kind add both to the in- 2222 terest in and clear comprehension of the subject, and when not carried to an ex- 4 6 8 10 treme are valuable. Addition. The 45 combinations of one-figure numbers should be reviewed, and in the first half year oral work of the types of 20 + 30, 25 + 30 should be taken, to be followed in the second half year by cases like 25 + 32 and 225 4- 32, where no " carry- ing " is involved. Written work with four-figure numbers in- cluding dollars and cents, should be given, but long 427 columns of figures should be avoided at present. 326 As already stated there is an advantage in intro- 452 ducing any difficulty in operation by using the com- 49 plete form. While, for example, the annexed prob- lem in addition is not designed as an introduction 24 to the addition of three-figure numbers, it illustrates 130 what is meant by the complete form. The teacher noo need have no fear that children cannot easily be brought to use the abridged form ; " the line of least 1254 resistance " will bring that about, while on the 94 The Teaching of Arithmetic score of a clear understanding of the operation this complete form is far superior to the other. It should also be mentioned that the pupil should at this early stage be taught to recognize his own liability to error and to do what every computer has to do, add each column twice, in opposite directions, to be sure of his result, to " check " it, as we say. Subtraction. This subject has been sufficiently treated under Chapter XI. The extent of the work is suggested by the work in addition, and of the various methods the addition or "Aus- trian " seems at present to be the best. Multiplication. This, with division, constitutes the special work of the year, addition and subtraction offering no essentially new difficulties. In the first half year it is customary to com- plete the tables through 10 X 10, and the products must be thor- oughly memorized not merely in tabular form but when called for in any order. The plan of carrying the tables to 12 X 12, while necessary in England on account s of the monetary system used there, has generally been discarded in America, it being felt that the time required for this 24 = 3 X 8 extra work could be better employed. In 270 = 3 X 90 the first half year multiplication may be carried so far as to include three-figure g Q4 = o x 208 multiplicands and one-figure multipliers, 208 and the work may at first be arranged 3 in the complete, and later in the com- mon abridged form as here shown. Since all such work is done in the class- room where the teacher can supervise it, there should be a time limit placed upon it, to the end that habits of rapidity as well as of accuracy should be acquired. In the second half year the work may usually 298 be extended to two-figure multipliers, in 43 which the complete form should again precede the common abridgment, as 894 = 3 x 2 98 here shown. There is also introduced 11920 = 40X298 . ... ... ,. ,. in this year such multiplications as 12814 = 43X298 that of $ 2 -75 by 7, thus preparing the way for decimal fractions. The lat- The Work of the Third School Year 95 ter are not, however, treated in this grade, and the work should not be made difficult by any unnecessary theorizing upon this subject. Division. In this year oral division by one-figure divisors is introduced for such simple cases as 484 -j- 2, 484 -^-4, 481 -r- 2, etc. Short division of numbers like 522 -r- 6, should be introduced by some such form as ) 5 22 the annexed. Such separations of the divi- 6)480 + 42 dend are made for the purpose of having the 8o+7 process seen in its simplest form, and teach- ers should write problems of this kind on the board often enough to make sure that the process is understood. The children should not be required to use this form, but should get to the practical work of division as soon as possible. In the second half year the two-figure divisor may be introduced, but since the greatest difficulty in di- 75 vision consists in the estimating 2I ) I 575 of the successive quotient fig- 1470 = 70 X 21 ., . . c ures, it is well to confine the IO r divisors, for this year, to those 105 5 X 21 whose unit places are at first o, then i, and finally 2. As an <^Q .,- early form for long division, the 2 j)S7~77 annexed algorism is suggested. 6.30 = 21 X $0.30 The use of United States money again brings in the decimal point 1-47 so naturally that the difficulty of 1.47 = 21 > decimal fractions is much dimin- ished when that topic is reached. The full form that may properly precede the common abridg- ment is here set forth. Scope of Work with Fractions. The pupil is now able to use halves, thirds, fourths, fifths, sixths, and eighths, or, if not, this work should be introduced at this time. Oral addition and sub- traction of fractions with a common denominator. The reduc- tion of halves to fourths, sixths, and eighths, and of thirds to sixths, is introduced by means of objects, the objects being dis- carded as soon as they have served their purpose. Fractional g6 The Teaching of Arithmetic parts of numbers of three figures or less, these being selected so as to be multiples of the denominator. Denominate Numbers. Here as in other grades it is neces- sary to review and frequently use the tables already learned. The table of square units is often introduced and extended to the square yard, although it may be postponed a year. The gill is added to the table of liquid measure, and the table of time is completed. Modern teaching finds it advisable to intro- duce the units of measure only as rapidly as the child develops the need for them and can therefore understand them. In all cases it is desirable to have the measures where they can be seen or in some other way appreciated. For example, when the acre is introduced, somewhat later, a piece of land near the school, approximately an acre in size, should be shown to the class. In the same spirit they should see a ton of hay or a ton of coal, a cord of wood where this is possible, a rod, a gill measure, and so on. It is very important that the great basal units used by our people should be visualized by the chil- dren, so that bushel, mile, ton, etc., shall not be mere words. Typical Problems. The following are suggested as two prac- tical sets of problems, adapted to this grade, each telling a story that may suggest other topics for original work by the class. Oral Exercise Some Home Meals 1. The coffee for our breakfast cost 6c., the potatoes 4c., the meat 32c., and the bread 4c. How much did the bread and meat cost? How much did all the food cost? 2. The oatmeal for a breakfast cost 8c., the milk 4C., the fruit ioc., the rolls and butter 5c., and the eggs 8c. How much did this food cost? 3. For a dinner the meat cost 3Oc., the vegetables 2oc., the dessert 2oc., the coffee I5c., and the other food I5c. Find the total cost. 4. The meals for a small family cost $1.70 on one day and $2.20 on another day. How much did they cost for these two days? The Work of the Third School Year 97 Written Exercise The toad is one of man's best friends. One toad will keep a garden of 800 sq. ft. free from harmful insects. 1. At this rate, how many toads would protect from insects a garden 80 ft. wide and 100 feet long? 2. The eggs of 4 toads were counted and found to be 7547, 11,540, 7927, and 9536. How many were there in all? 3. If one out of 50 hatched, how many hatched? (Divide all by 50.) If 715 of these were destroyed by other animals, how many survived? 4. If each of these survivors destroys insects that would cause $10 worth of damage, how much are they all worth to a village? . BIBLIOGRAPHY: The author's text-books on arithmetic, and the Wentworth-Smith series, set forth his views in detail. CHAPTER XVIII THE WORK OF THE FOURTH SCHOOL YEAR The Leading Mathematical Features. In this the last year of the primary grades it is well to feel that the essentials of arith- metic have all been touched upon. It is, therefore, desirable to review the four fundamental operations, extending the multipli- cation and division work to include three-figure multipliers and divisors. The common business fractions should also be in- cluded, with simple operations as far as multiplication. Number Space. In the first half year the numbers may extend to 100,000, and in the second half year number names may be given as high as a billion. The operations, however, should be confined to the smaller numbers of such business as can be appreciated by children of this age. Counting. The prime object of the counting exercises, the developing of the tables of addition and multiplication, has now been accomplished, except when it is desired to carry the multi- plication table to 12 X 12. In that case the counting may now be continued by n's to 132 and by I2's to 144. -Otherwise the only use of counting in this grade is for the purpose of review. Addition and Subtraction. There should be much rapid oral work with numbers like the following: 7 17 37 37 47 + 4 + 4 + 4+14+24 II 21 41 51 71 - 7 - 7 - 17 ~ 27 - 47 The written work should be undertaken with the aim of (i) accuracy, secured by always checking the result; (2) rapidity, secured by setting a time limit upon all work. Children should by no means neglect this matter of checks, since it is used in all the business world. Much; of the complaint of business men, 98 The Work of the Fourth School Year 99 that boys from the schools are always inaccurate in arithmetic, would be obviated if pupils were always required to check their additions by adding in the opposite directions, and their other results in some appropriate manner. In subtraction, for example, if the result is obtained by the "Austrian " method it should be checked by adding it to the subtrahend in the opposite direction. Multiplication and Division. No new principles are involved here, and the work of the preceding year is simply extended to include larger numbers. In some schools the multiplication table is extended to 12 X 12, although this is not important enough for most people to make it worth the while. It is a good plan, however, to learn all products less than 50, as 2 X 13, 3 X 15, 4X 12, and so on. since these are so often used in the purchases of the household. Even a child ought to know the cost of 2 Ib. of meat at 18 cents a pound, without using pencil and paper. The practical checks on multiplication and division are not advantageously discussed as early as this. Fractions. Here as later the work in common fractions should be confined to those needed in ordinary business, and at present to those from ]/ 2 to %. Of course there is no objection to an occasional example with denominators of two or three figures, but the day of fractions like -$zfa is past, decimal fractions having taken the place of all such forms. Children in this grade should also know that $ l / 2 = 50 cents, and $>4 2 5 cents. The opera- tions may extend as far as easy multiplications of an integer and a fraction, two fractions, or an integer and a mixed number. Unusual forms of operation, not practical in business, should not be given, and the teacher should resist all temptation to depart from this principle on any supposed ground of mental discipline. Decimal Fractions. A brief introduction to this subject, based on the work already given in United States money, may be al- lowed in this grade, although the serious treatment of decimals belongs later in the course. Denominate Numbers. The tables needed in business life are completed in this grade by adding that of land measure, and completing long and cubic measure. In the work of adding and subtracting compound numbers children should feel that there ioo The Teaching of Arithmetic is no principle involved that is not found in integers. For ex- ample, consider these two cases : 37 3 ft - 7 in - 3 lb - 7 oz. 25 2 ft. 5 in. 2 Ib. 5 oz. 62 6 ft. 5 Ib. 12 oz. In the first, because 7 + 5 = 12, which is I ten and 2 units, the I ten is added to the lo's. In the second, because 7 in. + 5. in. 12 in. or i ft., the I ft. is added to the feet. In the third, because 7. oz. + 5 oz. = 12 oz., which does not equal a pound, it is written under ounces. In every case the principle is the same, to add to the next order any units of that order that are found. In general we use compound numbers of only two denomina- tions, and it is on such numbers that we should lay the emphasis. The use of numbers of four or five denominations is now obsolete, and there is not enough disciplinary value in the sub- ject to warrant using them instead of the numbers of actual business. A!s heretofore mentioned, there should be an effort to have children visualize the standard measures of our country, such as the acre, mile, ton, and bushel. Teachers should be careful at this time that slovenly methods of statement do not become habits. Such forms as the follow- ing, for example, are inexcusable: 60 in. -f- 12 = 5 ft. 60 H- 12 = 5 ft. 60 in. H- 12 in. = 5 ft. If we wish to reduce 60 in. to feet we have three correct forms, any one of which is easily explained : 60 X Vi2 ft. = 5 ft. 60 in. -r- 12 in. = 5, the number of feet, 60 -T- 12 = 5, the number of feet. If slovenly forms are allowed here they must be expected in all subsequent grades, and they must be expected to lead to slovenly thought in the treatment of all kinds of problems. Review. At the close of the year there should be a review of all the essential features of the work in the primary grades. This requires skill on the part of the teacher lest it become stupid and so wearisome as to lose its chief value. Original local The Work of the Fourth School Year 101 problems to test the children in the four fundamental operations with integers and (as far as they have gone) with fractions, will usually render the work interesting and will hold the attention. Nature of the Problems. Here as elsewhere the problems should touch the children's interests and be adapted to their mental abilities. The following may be taken as types: Oral Exercise 1. Tell the cost of some kind of cloth. How much will io l /2 yd. cost? 2. Tell the cost of a pair of shoes. How much will 2 pairs cost? 3. If a man earns $3 for 10 hours' work, how many hours must he work to earn enough to buy his daughter a pair of shoes at $1.50? 4. How many hours must he work to earn enough to buy a $6 suit of clothes for his son? Written Exercise 1. Sarah's mother bought 4Y 5 yd. of cloth for a cloak, at $1.25 a yard. What did she pay for it? 2. She also bought 3^ yd. of lining at SQC. a yard, and 4 l /4 yd. of braid at 2oc. a yard. How much did these cost? 3. She also bought 6 pearl buttons at $1.50 a dozen, and 2 spools of silk at 8c. a spool. How much did these cost? 4. The dressmaker charged $5 for making the cloak. What did materials and making cost? .5. John's mother bought 2^ yd. of goods for a coat, at $1.20 a yard, and 2^ yd. of lining at 48c. a yard. How much did these cost? 6. She also bought a dozen buttons at 25c. a dozen, and 2 spools of silk at 8c. a spool, and paid $3 for making. How much did the coat cost? CHAPTER XIX THE WORK OF THE FIFTH SCHOOL YEAR The Leading Mathematical Features. There should in this year be a thorough review of the fundamental operations with integers. This should be followed by the same operations with the common fractions and denominate numbers of business. Percentage may be begun, although in some places it is better to postpone this until the following year. Review. There is usually a new text-book begun in this grade, and this, if properly arranged, offers plenty of material for the review above mentioned, with numbers that are appro- priately larger. Teachers should undertake this review in the spirit and for the reason suggested in Chapter XVI. Text-book. The new text-book begun in this grade will natur- ally be topical in its arrangement, that is, each general topic like percentage being treated once for all; or it will be on the plan of recurring topics, a subject like percentage being met two or three times. As has already been said, each of these types has its advantages. If the school chooses one with recur- ring topics that can probably be followed rather closely. If on the other hand it adopts one arranged by topics there are two courses open : ( i ) the teacher may select from the various chap- ters such material as fits the course of study in use in the par- ticular locality, a task of no great difficulty; (2) the book may be followed closely, the pupils' work becoming purely topical. We are apt to condemn the latter plan because it is old, but perhaps on that very account it should be commended. The world has used it, and used it successfully, and it has the merit that it brings a feeling of mastery, a sense of thoroughness, and a development of habit that is sometimes lacking with more modern text-books. In general it may be said to depend upon the school as to which type of book is the better, and as to which plan of using the topical book is to be preferred. In a 102 The Work of the Fifth School Year 103 school system with a reasonably permanent staff of teachers, with adequate supervision, and with teachers' meetings that allow classes to keep in touch with one another, the book with recurring topics, or at least the course arranged on this plan, is undoubtedly the better. It is more psychological and it allows for a better grading of material. On the other hand where teachers change frequently, as in rural schools, it is safer to use the topical book and to follow it rather closely. In this and the following chapters the arrangement by recurring topics is followed, and any topical text-book can easily be adapted to the sequence suggested. Number Space, This number space is now unlimited, but names beyond billion are of no particular importance. Large numbers should always represent genuine American conditions. It is better to perform several operations on the ordinary num- bers of daily life than to perform one on an absurdly long number; but on the other hand, a reasonable number of opera- tions on large numbers that represent real business cases are to be commended. Addition. Larger numbers and longer columns may now be used, but there is a limit to this matter. In general, the numbers used by the average citizen are the ones to drill children upon. Children should be encouraged to read columns as nearly as pos- sible as they read a word. When we seek the word " book " we do not think " b," " o," " o," " k," we think "book" with- out any spelling ; so when we see the annexed column we should not think, " 6 and 3 are 9, 9 and 3 are 5 12, 12 and 5 are 17," nor even " 6, 9, 12, 17," if we 3 can do better than this. Probably we cannot train 3 our eyes to see 17 at a glance, as we seek " book," 6 but it is well to encourage children to look at this as 9 + 8, thinking of the 6 and 3 as 9, and the 3 and 5 as 8. But, however we think of such a column, we should always check our result by adding in the reverse order. If teachers do not think this necessary, let them add twenty sets of say ten five-figure numbers each, working rapidly, and see how many mistakes they themselves will make. Subtraction. This subject has been sufficiently discussed on page 45. The important matter is not now the explanation, IO4 The Teaching of Arithmetic for the technique has already been learned; the operation, ac- curately and rapidly performed, is the desideratum, the check being of great importance in securing the essential accuracy. Multiplication. It is now advisable to let the children know some good, practical check on their work in multiplication, such as computers actually use. Of the checks, the simplest is that of " casting out 9's." 1 Division. The children are now old enough to understand the two forms of division illustrated by the following: $125. ^-$5 = 2$ $125 -4- 25 = $5 There are no generally accepted names to distinguish these, " measuring " and " partition " not meaning much to children. It suffices that it is clear that there are these two forms, and to see that we avoid such inaccuracies as $125 -r- $25 = 5 cows. Factors and Multiples. This subject formerly played a. very important part in arithmetic, when large fractions had to be reduced to lower terms. With the introduction of the decimal fraction about 1600, however, it lost much of its former im- portance and need play but a small part in the arithmetic of to-day. 2 Common Fractions. Some objective work will still be neces- sary in treating common fractions but it should be dispensed with as soon as possible and the material should not be of one kind alone. In the operations children should not be required to give very elaborate explanations, although they should see clearly the reasons at the time they learn the processes. This has been discussed already in Chapter IX and may, therefore, be dismissed at this time. Denominate Numbers. The operations with these numbers should be a part of the work of the year, but only practical cases should be taken. To divide a compound number of four 1 The explanation of this process is too long to be given here. The reader may consult the author's Handbook, p. 57, Beman and Smith's Higher Arithmetic, or the appendix to the Wentworth- Smith Complete Arithmetic and the Arithmetic, Book III. 2 For a theoretical treatment of the subject from the advanced stand- point, consult Beman and Smith's Higher Arithmetic. The Work of the Fifth School Year 105 denominations by another one of three, for example, consumes time and patience to no worthy purpose. How to Solve Problems. Inasmuch as the children now begin to consider problems of more than two steps, it becomes neces- sary to devote more attention to the methods of solving ex- amples. The step form of analysis, therefore, has a legitimate place in this year's work. If teachers hope for exactness of thought they must insist upon accuracy of statement in these written exercises. Percentage and Decimals. The study of decimal fractions may safely be undertaken in this grade, and this may be fol- lowed, if desired, by an elementary treatment of percentage. If at the outset children understand that 6% is only another way of writing yf^ and 0.06, there will be but little difficulty in introducing percentage. One important feature is the inter- change of the per cent forms, decimal fractions, and common fractions, as for example, in ]/$ =-r^= 0.25 = 2$%. It is better not to introduce any formulas or rules in such work in percentage as may be taken at this time, but to analyze each problem as it arises. In the next school year it is allowable to reverse this policy. Discount. Of all the applications of percentage the most common is 'discount, and it is at the same time the simplest. This topic may, therefore, be introduced in this grade, the other applications being reserved for the sixth year. Nature of the Problems. The great industries of the country may be taken up at this time as a profitable field for the applica- tions of arithmetic. Children now begin to know enough geogra- phy to permit of this wider view, and problems that relate to their own country have an interest that the traditional ones about the man who " owned a field of corn " lacked. Such problems are not statistical to the extent that their data are to be memor- ized, but they state real conditions instead of false ones. Of problems suited to this grade the following are types relating to the production of corn, one of the great food products of the country. The greatest corn-producing states are Iowa, Illinois, Nebraska, Missouri, Kansas, and Indiana, and such work may be taken in connection with the study of the geography of these io6 The Teaching of Arithmetic sections whenever this can be brought about without too great change in the curriculum. 1. When this country produced 2,105,102,400 bu. of corn a year, averaging 25 bu. to the acre, how many acres had we in corn? 2. If 3 bu. of corn could then be bought for $i, what was the total value of this yield of 2,105,102.400 bu? 3. When Iowa's annual product amounted to 305,800,000 bu., this was how many times the 440,000 bu. produced by Maine? 4. To transport 1000 Ib. of corn from St. Louis to New Orleans by river costs $i. How much will it cost to transport 1750 tons? 5. If the average value of corn for each of the 46,610 acres given to it in Connecticut in a certain year was $21, and for each of the 4,031,600 acres in Indiana $13, what was the entire value of the corn crop of each state? 6. If the average annual corn crop per acre is 40 bu. in Wisconsin, 36 bu. in Maine, 37 bu. in New Hampshire, 38 bu. in Massachusetts, 38 bu. in Indiana, and 38 bu. in Iowa, find the average by adding and dividing by 6. CHAPTER XX THE WORK OF THE SIXTH SCHOOL YEAR The Leading Mathematical Features. The leading features of this year should be percentage and its applications, particu- larly to discount, profit and loss, commission, and interest. Ratio and simple proportion may also be included. The General Solution of Problems. Since the work in per- centage introduces the pupil to the problems of business, some of which become rather intricate in the later school years, it is well at this time to take up rather systematically questions of the solu- tion of problems in arithmetic. To this end there should be con- sidered exercise in analysis in general and in unitary analysis in particular, and the equation may well begin to find place in the mental equipment of*jjae* child. As to the matter of analysis no question will be raised, but as to introducing the letter x some teachers are In doubt. When, however, we come to consider that it merely replaces- an awkward symbol that has long been used, and makes the work much clearer, the objection cannot be main- tained. For example, 2 + ( ?) = 7 is sometimes used as early as the first schodl "y.ear ^.ttfis^ho wever, is only a complicated way of writing 2 -K$-= 7, tr^e two meaning exactly the same thing. Similarly, 4 : 7 =M2*: (?) is only an awkward way of writing what is equivalent*? x 7 12 \ 4 the latter being in every way simpler of understanding and easier of solution. Theje are several classes of problem in per- centage that are made clearer' by the use of this convenient x, and its use is quite as arithmetical as algebraic. Percentage. In this work special attention should be given to the common per cents and fractions of business, such as and so on. 107 io8 The Teaching of Arithmetic In the matter of solution, the x should be used in those inverse cases where it makes the problem clearer. Such is the case of finding the cost of goods that sell at 10% above cost, and sell for $126.50. Here we have, if x represents the cost, x + .\QX = $126.50 1. 10^ = $126. 50 X = $126.50 -4- 1. 10 #==$115 Other forms of solution might be used, but this is the most satisfactory. Discount. This being the first and most important of the applications of percentage, considerable attention should be de- voted to it. The case of several discounts may, however, be postponed until the following year. Profit and Loss on Purchases. This topic, so closely con- nected with the business world with which the child is now coming into closer contact, may claim to rank second in impor- tance among the applications of percentage. The principles involved are very simple, particularly if one allows the letter x to throw light upon all inverse problems. The examples should follow as closely as possible the common business customs of the mercantile world. Commission. This topic ranks possibly third in importance among the applications of percentage. A considerable field of applications exists, particularly in relation to the sending of farm produce to the cities. The problems can, therefore, be made to seem real to the children, whether they live in the country or see farm products for sale in the city. Interest. This subject may already have been met by the children. It is now taken up and extended to more difficult questions. Only real cases should, however, be considered. For example, in this school year, at least, there is little advantage in trying to find the capital, given the rate, time, and interest. It is better to spend time in writing promissory notes and in comput- ing the interest, than to put it on questions that seldom arise in business life. If we wish more complicated problems they are easily secured from genuine mercantile sources. Ratio. This may be introduced this year or reserved for the seventh grade. It was formerly introduced merely as an intro- The Work of the Sixth School Year 109 duction to proportion. It is easy, however, to see that it may be of some i^se by itself, and teachers are advised to consider this phase of tfce subject. We mix fertilizers on the farm in a given ratio, we find ratios of attendance to absence in the school, and the term is used in the same way in business life. Proportion. This subject may also be delayed another year. It has lost a good deal of its importance of late. A proportion is, as shown on page 107, merely one method of writing a simple equation, and with the letter x allowed in school, the equation form is likely to replace that of proportion. When this is not the case, ordinary analysis is likely to be substituted for pro- portion. For example, consider this problem: If a shrub 4 ft. high casts a shadow 6 ft. long at a time that a tree casts one 54 ft. long, how high is the tree? Here we may write a proportion in the form, 6 ft. : 4 ft. = 54 ft.: (?), not attempting to explain it, but applying only an arbitrary rule. This is the old plan. Or we may put the work into equation form. 54 6 and deduce the rule for dividing the product of the means by the given exteme. Or we may take the same equation and get our result easily by multiplying these equals by 54, giving * = 3 6 Or we may say : If a 6 ft. shadow is cast by a 4 ft. object, a I ft. shadow would be cast by a */e ** object, and a 54 ft. shadow would be cast by a 54 X 4 /e ft. object, or a 36 ft. object. Of these plans the first is the most difficult to explain; the rest are equally easy, and the third is the shortest. Measures. The work in measures this year may be confined to simple surfaces and solids, and may properly include practical cases of house building, plastering, carpentering, and the like. Here is a real field, interesting and profitable. Proportion leads to exercises in similar figures, and this has some excellent appli- cations in lumbering and in carpenter's work. Nature of the Problems. In each succeeding year the prob- lems now come to relate more and more to the industries of the no The Teaching of Arithmetic people, and the range of applications becomes very great. The farm child learns not only of his own surroundings but of the great industries of the city, while to the city child the great story of the soil and its products opens up a new world. The follow- ing farm problems may be taken as types of the problems suited to this grade: 1. A farmer puts 5 acres into celery, setting out 20,000 plants to the acre. The yield being 1,500 doz. heads to the acre, what is the ratio of the plants matured to the others? ' ... 2. He pays $95 an acre for seeds, fertilizers, labor, and other expenses, and sells the crop at I5c. a dozen heads. What is his profit on the 5 acres ?j? fciTO.oo 3. Another farmer tries setting out 30,000 plants to the acre, but only 80% mature, and these are so small that he has to put 16 in a bunch to sell for a dozen, and then gets only i4c. a bunch. His expenses are $100 an acre. At this rate what is his profit on 5 acres ?f JTlTO.O* 4. A farmer has a 3O-acre meadow yielding i l /2 tons of hay to the acre. If by spending $300 a year for fertilizers, he can bring the yield to 4 tons to the acre, how much more will he make a year, hay being worth $8 a ton? 5. A farmer reads that a good mixture of seed for his meadow is, by weight, as follows: timothy 40%, redtop 40%, red clover making up the rest. At 40 Ib. of seed to "the acre, how many pounds of each should he sow? t to "T- I r> Jf-- t 6. The following is, by weight, a good mixture of seed for a ~J pasture: Kentucky blue grass$25%, white clover \2,y 2 %; per- ennial rye 28%%, red fescue $%, redtop 25%. At 32 Ib. to the acre, how many pounds of each are used? 7. A cow weighing 1000 Ib. consumes the equivalent of 3>4 tons (2000 Ib. to the ton) of dry fodder a year; a loo-lb. sheep, 770 Ib. ; every ton of live pork, 12 tons ; and every ton of live horseflesh, 8.4 tons. Each class of animals consumes what per cent of its own weight of drv fodder a year? T ^ CHAPTER XXI THE WORK OF THE SEVENTH SCHOOL YEAR The Leading Mathematical Features. As in the preceding grade, it is well to begin by a general review of the fundamental processes from a higher standpoint than before. Ratio and pro- portion are usually completed in this year, whether introduced here for the first time or not, and the applications naturally cover a broader field. Percentage is the leading topic of the year. Our Numbers. The children are now ready to consider the writing of numbers from a higher standpoint, to know something of the interesting history of the numerals they use and of the science of arithmetic that they are studying. The story of the Roman numerals, 1 and that of the Arabic numerals make these subjects seem more real at this time. The difference between a uniform scale, as seen in our system of money, and a varying one, as seen in the English system, should also be explained, and the advantage of the former understood. The relation be- tween integers, the various kinds of fractions, and compound numbers, may now understandingly be taken up. The Fundamental Operations. These may now be reviewed in such way, that is by the introduction of such new material, as to maintain the interest even in an old subject. This is par- ticularly true if the teacher will now and then suggest such short methods as may be found in most of the advanced arithmetics. The check of casting out nines should now be used for all products and quotients. It is simple, it takes but a moment, and it checks most of the errors that are liable to arise. It cannot be too much impressed upon teachers and pupils that both are very liable to errors in all kinds of calculation, and that they, like business computers, should always apply some kind of check to every result obtained. Some teachers feel that 1 This is told in condensed form in the author's Handbook to Arithmetic. See also the Bibliography at the close of Chapter I. ill 112 The Teaching of Arithmetic the work should be so accurately done that checks should be unnecessary. This is a good theory, but practically it will not work even with the ones who advocate it. No good professional computer would think of leaving his results without checking them, and if a professional will not do this, why should we expect a child to be so infallible as to do it? Measures. All tables of measure in common use should be reviewed in this year. If, in this review, some historical notes are given on the origin of such measures as the yard, inch, foot, mile, quart, gallon, and acre, the pupils will find the work taking on a new interest. Teachers are advised that it is of little value to memorize facts that will not be used in practical life. If we wish to know the number of cubic inches in a bushel we may go to an encyclopedia or a dictionary; it is surdy inadvisable to burden our minds with such details. Longitude and Time. This subject has greatly changed within a few years. To-day most of the civilized world uses some form of standard time. Therefore, our attention may properly be confined to the geographical principle involved, to the prob- lem of standard time, and to the question of longitude at sea. Teachers are urged not to allow slovenly work in this subject under the plea that bad forms bring true results in a shorter time than good forms. This matter has been sufficiently dis- cussed on page 30, and the chapter on longitude and time seems to be one of the worst offenders in all arithmetic. A form like 45 -r- 15 = 3 hrs. is false and serves to undo all of the good to be derived from the topic. Percentage. This topic, so vital in business life to-day, should be touched upon several times in the elementary school. If the work is sufficiently progressive the pupils will not find that " the edge of interest " is worn off. In this year there should be a good deal of oral work in the common per cents of business, pupils coming to feel that pencil and paper are unneces- sary in finding 12%%, 25%, 3^/3%, 50%, 66 2 / 3 %, and 75% of ordinary numbers. As to the use of terms like " base," " rate," " percentage," " amount," and " difference," there is little that can be said in their favor. They were invented in the rule stage of arithmetic, and have served their purpose. Of course, we need " rate," it being a stock term of the business world. " Percent- The Work of the Seventh School Year 113 age " is, however, rather confusing than otherwise, ( i ) because it is understood by the pupils as the name of the subject as a whole, and (2) because the business world does not use it quite as the school does. " Base " means so many things in mathe- matics that its use is equally confusing, while of " amount " and " difference " this is still more noticeably the case. On the whole, therefore, it is as well not to use these terms, although they are found in most of our leading books to-day because of the demands of teachers. It should also be remarked that, if the use of x is allowed, there is no excuse for the old formulas of percentage. They are nothing but condensed rules ; if they are not explained they defeat part of the purpose of studying arithmetic; if they are explained they are much harder than the equation form with the single letter x. It is well to bear constantly in mind, in the midst of the large number of possible cases of percentage, that the two important things in the subject are these: (i) to find some per cent of a given number, and (2) to find what per cent one number is of another. All the rest is relatively unimportant, and on these two the emphasis should accordingly be laid. Simple Interest. This is the leading application of percentage in this year, and the attention of pupils should be concentrated on the single problem of finding interest in practical cases. To find the time, given the principal, rate, and interest, is of very slight importance, and so for other similar cases ; but to find the interest, that is the great point. Ratio and Proportion. This work should, as stated in the preceding grade, be confined largely to the treatment of practical questions, and there are only a few where this subject can be used to real advantage. These are chiefly related to similar figures, although some other questions, like those of simple physics, enter. Compound proportion has little reason to claim a place in our schools to-day. If explained, the process is a very hard one; if not, it is a useless one, since we now have better methods of solving problems. Nature of the Problems. With each succeeding school year the children develop new interests and come nearer to the great world that they are soon to enter. The range of topics is now 114 The Teaching of Arithmetic practically unlimited, and the opportunities for offering series of related problems are excellent. As a type of such problems the following may be given, appealing this time to the girls, who are usually rather neglected in the matter of applied arithmetic : Dressmaking Problems Written Exercise 1. A dressmaker bought 16 yd. of velvet at $3 a yard, selling 9 yd. at a profit of i6 2 /^% and the rest at a rate of profit half as great. What was the rate of gain on the whole? 2. She bought a 25~yd. box of chiffon velvet at $4 a yard, with 10% off for cash, selling it at $4.35 a yard. What was her gain per cent? 3. She bought a 75-yd. piece of silk skirt lining at 65c. a yard. She sold 28 yd. at 9oc., 15 yd. at 95c., and the remainder, at the close of the season, at /oc. What was her per cent of gain ? 4. She bought a 5o-yd. piece of silk waist lining at 75c. a yard. She sold 12 yd. at $i and 10 yd. at 95c., but the remainder, being kept in stock over the season, had to be sold at 65c. What was her per cent of gain or loss? 5. She bought a 2O-yd. silk dress pattern at $2.10 a yard, being allowed, as a dressmaker, a discount of $%, and 6% off for cash. She charged her customer the marked price, $2.10. What was her per cent of profit? 6. She charged her customer $25.50 for 3 yd. of Honiton lace, which had cost her $7 a yard. What was her per cent of profit ? 7. She charged her customer $2 for findings for the dress. These consisted of 4 spools of silk at IDC. each, i spool of thread at 5 c -> 3 yd- of featherbone at ioc., a card of hooks and eyes at 8c., skirt braid i6c., plaiting 3oc., waist binding 3Oc., and collar ioc. What was her gain per cent on the findings? CHAPTER XXII The Leading Mathematical Features. The work this year is in the line of business applications, including advanced mensuration. Business Applications. The boy and girl should now begin to feel that the world of business and of life is opening before them. It should therefore be the duty of the school, even more than in the preceding grades, to apply arithmetic to the genuine problems of life, particularly with reference to the common occu- pations of the people. Banking. In banking, for example, we should not seek to train accountants or bookkeepers or cashiers, but we should seek to give a fair idea of the duties of these men in the ordinary savings bank and bank of deposit. A girl, for example, needs to know how to deposit money in a bank and how to draw checks as well as a boy, and such operations should become as real as the school can make them. School banks, with deposit slips, checks, bank book, cashier, paying teller, and receiving teller, should assist in this work. Partial Payments. This subject has not the practical value that it had when banks were not so numerous as now, and when their machinery was not perfected. The old-style problem in partial payments should therefore give place to the more prac- tical cases found in our best modern books. Partnership. This is another subject that has entirely changed within a short time. The stock company (corporation) has largely supplanted it, save in its simplest form. The work of the schools should therefore be confined to this common form, the obsolete ones being supplanted by work on corporations. Simple Accounts. It is not worth while to teach an elaborate form of bookkeeping to the average citizen. On the other hand it is necessary that every one should know how to keep simple accounts, and this work should be taken up in this year. It should relate to the income and expenditures of daily life, in the "5 u6 The Teaching of Arithmetic home, on the farm, or in the shop, rather than to the technical needs of the merchant, the latter being part of the special train- ing of the individual who enters this line of trade. Exchange. Here again there has been a great change within a few years. The form of time draft given in most of the old- style arithmetics has given place either to sight drafts or to another kind of time draft. Teachers should therefore be particular to use only those types that the ordinary citizen meets to-day, about which girls and boys alike should be informed. In connection with this work a short talk upon the clearing house, upon which any bank will gladly inform the teacher, will add new interest. The Metric System. This system might be taught much earlier than the eighth school year, and there would be some advantage in so doing. But when we consider that it is not yet used practically by many Americans, it seems as well to postpone it until this time. There are three chief reasons for teaching it now: (i) General information requires us to know a system that is used by a large part of the civilized world, excluding the English-speaking portion; (2) it is used in all scientific labor- atories in America; (3) our people should be sympathetic with a system that is liable to replace our own before long in all matters relating to our growing foreign trade; if we sell ma- chines abroad, the measurements must be metric in most cases, and to foster this trade many of our skilled workmen will eventually need to use these instead of the awkward ones with which we are familiar. At the same time we must not go to an absurd extreme, but must remember that our common system is the one that the people use and that the children must know before all others. In teaching the metric system the results will be poor unless the children use the actual measures and come to visualize the basal units as they should in their own system. Taxes. This topic, like others of practical life, should be treated from the standpoint of local conditions as far as possible. It should include the question of tariff, and a few brief talks on civics should make the whole question a real one for the pupils. Insurance. This subject has become so technical that all that the schools can hope to do is to give a general conception of the The Work of the Eighth School Year 117 work of the various kinds of companies, and to confine the prob- lems to the simplest practical cases that the people need to know about. We should not attempt to enter upon the technicalities of agent work, nor to do more than explain briefly some of the common types of policy. Corporations. As remarked under Partnership, the corpo- ration has, for good or evil, replaced the individual in large business ventures. Our schools must, therefore, adjust their work to this change. Pupils should know what a corporation is, its chief officials, how it is legally organized, what stocks and bonds are, how dividends are declared and paid, and the legiti- mate work of stock exchanges. On the other hand the schools cannot be expected to teach the technicalities of the stock brok- er's office, nor to supply information beyond that needed by the general citizen. The newspaper stock reports furnish an excel- lent basis for the practical problems that the case demands. Powers and Roots. For purposes of mensuration square root is necessary. Cube root may well be delayed until the pupil studies algebra, because it has so few practical applications. Even square root is more valuable as a bit of logic than as a practical subject, since those who use it most employ tables. The explanation, therefore, is even more important than the technique of the work, and children of this age can easily com- prehend it, either by the use of the diagram or by the formula, the latter being quite easily understood by this time. Mensuration. This work is now completed so far as the needs of the average person are concerned. The teacher should use simple models that can be made in the school room, as sug- gested in the best arithmetics. It is not expected that strict geometric demonstrations can be given, but it is entirely possible to avoid arbitrary rules by giving enough objective work to make the matter clear. It is not advisable to introduce work that is not used in ordinary life, such as finding the volume of a frustum of a cone, there being a sufficient amount of more important work to occupy the time and attention of pupils. Nature of the Problems. The problems should appeal to the business needs that are soon to come to the children, and the following are suggested as types: I. A boy who has been working this year at $25 a month is offered either an increase of 20% for next year or a salary of $7 n8 The Teaching of Arithmetic * a week. Which will bring the more income, and how much more per year? (Use 52 wk.) 2. A girl who has been working in a factory at $21.67 a month is offered an increase of 10% where she is or a salary of $5.60 per week elsewhere. Which will bring the more income, and how much more per year? (Use 52 wk.) 3. A boy went to work at 9