THE SCIENCE y ws 4p vé é on ly i % ~f4 a. —_ —? ~ = Y ens Br ws A aes — Gor a) a MATHEMATICS LISRARY wt t Sing CC. es THE SCIENCE OF 0 mm AND Their * Practical * Application FOR TEACHERS AND PRIVATE LEARNERS BY MERRITT L. DAWKINS DOWNING, MO. PEERLESS PUBLISHING COMPANY. 1890. Entered according to act of Congress, in the year 1890, by MERRITT L. DAWKINS, In the Office of the Librarian of Congress at Washington. ; PRINTED AT THE RECORD PRINTING HOUSE, DOWNING, MO. ISMy 44 Spoes evel. Quer, 513 paza MATHEMATICS LIBRARY I NTRODUCTORY. ———— The design of the author in preparing this little volume has been to embrace, within moderate space, a practical and useful treatise on ARITHMETICAL SCIENCE, and to place it within the reach of every home and every business office throughout the land. The author does not arrogate to himself the first knowledge of the methods found in this work. He sim- ply contends that no similar work issued previous to the date of his copyright is so convenient, instructive and satisfactory. By the utmost brevity and precision the author has been enabled to compress a vast number of useful methods into a small compass and by eliminating a few subjects which serve rather to perplex than to en- Jighten, he has, in the opinion of those competent to judge, produced a work that will prove valuable to the business man, the farmer, the mechanic, and the large class of people who have not had the opportunity or ability to master the various technical terms of arithmetic, and to whom many of its principles and processes have heretofore been laborious and difficult. The author has availed himself of many valuable hints and suggestions from business men, practical teachers, 6022183 4 INTRODUCTORY. and educators, all of whom he desires to thank most cordially for the aid they have rendered. The greatest care has been taken to ensure accuracy, but where imperfection is so general in works of this class, it is too much to hope that errors have not crept in. Should the reader note any such, the author will deem it a favor to be informed of them, with a view to their correction in subsequent editions. Trusting that the work will in some measure supply the popular demand for a Practican AritHmertic, the author presents his work to the public. M.: dae; September 1, 1890. NOTICE. We solicit correspondence with teachers and others who are open for a profitable engagement. This is by universal consent the best selling book pub- lished, and if you want to make Bia Money secure an agency for this great work without delay. Sample copy mailed on receipt of one dollar. PEERLESS PUBLISHING Co. SGIENGE OF NUMBERS. ~~ ——— DEFINITIONS. 1. A Number is a unit or a collection of units. 2. An Even Number is one that is exactly divis- ible by 2. 3. An Odd Number is one that is not exactly divis- ible by 2. 4. A Prime Number is one that has no exact di- visor besides itself and 1. 5. A Composite Number is one that has exact divisors besides itself and 1. 6. An Abstract Number is one that denotes no particular thing. @. A Denominate Number is one which denotes some particular thing; as two pounds, four boys. $. An Integer is a whole number. 9. The Complement of a number is the difference between it and a unit of the next higher order. 10. The Supplement of a number is the difference between it and a unit of the next lower order. 11. The Reciprocal of a number is 1 divided by that number. ADDITION. >< 2. Addition is uniting two or more numbers into one. IS. The Addemnds are the numbers to be added. if. The Sumi is the result obtained by adding. 15. The Sign of Addition is the perpendicular cross, +, and is read Pius. 16. The Sign of Equality consists of two hori- zontal parallels, = , and is read EQUALS, Or, IS EQUAL TO. iv. WRapidity and acuracy in addition can be se- cured only by frequent and careful practice. These two acquirements are the most Sse qualifications of an accountant. 18. Careful Practice will enable the student to add several columns at once. This method cannot well be extended to more than three columns with any prac- tical advantage, unless the columns are incomplete. 19. The Work should be tested by adding in an opposite direction from that in which the additions were _first made. 20. When there are but Two Numbers to be added, it is more convenient to begin at the left to add, observing to carry ONE when the sum of the next lower figures is more than 9. ADDITION. 7 21. Make Combinations of tens when possible and think resutts only. Thus, instead of saying 3 and “ai 7 and 8 are 15, think 8, 7, 15. 22. Numbers increasing by a common difference, as 2,4, 6, 8, may be added by multiplying the first and last by the number of addends. 23. Write Totals of each column under each other, by one of the two methods shown below, and then com- - bine them in one result. The first method is perhaps the better, as it obviates the difficulty of carrying tens. 24. 1. A has 798 dollars, B 875 dollars, and C 769 dollars. How much have they together? $2442. PROCESS. ANOTHER PROCESS. 22 798 2'2 22 875 2/4 22 769 24 2442 2. I owe one man $375, another. $280, a third $564, a fourth $119, a fifth $75. How much do I owe? 7 $1413. 3. Paid for coffee $245, for tea $325, for sugar $196, for flour $217, and for spices $273. What did all cost? $1256. 4, Je) a" we) jet i | —" ie 2) bo —_ ho pis bo ~J vs = 1S) wy) Yo oe | 10) 15) 20) 25! 30) 35) 40) 45) 50) 55) 60 72 a" Ts bo peed bo QO do or bo bo > Ne) On o> Ss oo =~] S ~] ~] QO ns fo on eer ot pe —" iw) — CO bo a Yo er — bo cm“ io.6) or ae or) i=) er) er) | 16 24 32) 40 48) 56 64 72 80 88) 96 | | 63, 72, 81) 90 99 108 110 120 121132 182)144 = jas, io 8) bo IN vo or) > ot Or 1s nd —) ho =, or = S © ~I = ee) ss c© 8) fae c =) et | bk | = bho | bo H> |b wo | o9 S| & Hm | Go | l| on Cle ~1| D> bo 1S oo;~x ml co | 00 S| DW am Ole HS! —) nh | — Sn NUMBERS LESS THAN 20. 43. The following method will be found valuable in Multiplying Mentally any two numbers less than 20. 44. 1. Multiply 16 by 14. 224. é PROCESS. 16 14 200 24 224 Expranation.—Add the unit figure of one number to 16 MULTIPLICATION. the other number, annex a cipher, and to the result add the product of the unit figures. After a little practice the operation can be performed mentally, thus extending the multiplication table to the twenties. 2. How many miles will a man travel in 16 days, if he travel 18 miles per day? 288. 3. If there are 17 yards of cloth in one piece, how many yards in 13 pieces? 221. 4. Ifaman can dig 19 bushels of potatoes in one day, how many bushel can he dig in 16 days? 304. 5. Ifa boat can sail 18 miles per hour, how many miles can she sail in 14 hours? 252. EN dS DIN Gra VWVils ee CP EL Bi: 45. To Multiply when there are ciphers at the right of one or both factors, proceed as if there were no ciphers, then annex the ciphers to the result. 46. 1. Multiply 3200 by 60. 192000. PROCESS. 3200 60 192000 2. What will 42 cows cost at 40 dollars a head? $1680. 3. What costs 56 yards of muslin at 30 cents a yard? $16.80. 4. What will 21 horses cost at the rate of 80 dollars per head? $1680. 5° What will be the cost of 70 acres of land at 24 dollars per acre? $1680. 6. Ifa ship sail 28 miles an hour, how many miles will she sail in 60 hours? 1680. MULTIPLICATION. 17 SMALL NUMBERS. 47. The Method of multiplying by 11 and other small numbers is explained below. 48. 1. Multiply 236 by 11. 2596. PROCESS. 2596 ExpLanation :— Write the unit figure and then add the digits, two at a time, beginning at the right, finally writ- ing the left hand figure. 2. Multiply 423 by 16. 6768. PROCESS, 423 16 6768 Expianation:—Multiply through by 6 and carry the succeeding figure of the multiplicand each time, finally writing the left hand figure of the multiplicand increased by the units to carry from the next lower order. 3. Multiply 123 by 24. 2952. PROCESS. 123 24 2952 ExpLaNaTion:—Proceed as above, but carry double the succeeding figure each time, or double the multipli- cand mentally and multiply by half the multiplier. 4. Ifa clerk receive 125 dollars a month, how much will he receive in 16 months? $2000. 18 MULTIPLICATION. 5. If it takes 132 laborers 18 months to build a rail- road, how many months will it take 1 man to build it? 2376. 6. Allowing 365 days to the year, how many days has a man lived who is 24 years old? 8760. 7. Sound moves 1142 feet in a second, how many feet will it move in 27 seconds? 30834. 8. A cooper can make 127 barrels in a week. How many can he make in 17 weeks? 2159. 9. Ifaman put 28 dollars in a savings-bank in a month, how much will he dposit in 14 months? $392. FACTORING. 49. The ordinary method of factoring the multiplier when it is a Composite Number requires no ex- planation. 50. To Multiply when one part of the multiplier is a factor of another part, the following contraction will be found valuable. 51. 1. Multiply 421 by 312. 131352. PROCESS. 421 312 1263 3052 131352 Expianation.—Multiply first by the 3, and then this result by 4, writing each partial product in its proper order. 2. If an ocean steamer sail 287 miles per day, how many miles will she sail in 84 days? 24108. MULTIPLICATION. 19 3. Sold my farm of 248 acres at 186 dollars per acre. How much did I get for it? M6128. 4. How much will it cost to lay 325 miles of ocean cable at an expense of 217 dollars per mile? = $70525. 5. What will be the cost of 239 bushels of potatoes at 84 cents per bushel? $200.76. MULTIPLIER NEAR 100, 1000, ELC. 52. The method of Multiplying by a number a little less than a unit of the next-highest order is illus- trated below. 53. Ll Multiply 135 by 98. 13230. PROCESS. 13500 270 13230 ExpLaNnation.—Annex two ciphers to the multiplicand, thus multiplying by 100, and from the result subtract the product of the multiplicand by the complement of the multiplier. 2. What will be the cost of 216 bushels of corn at 97 cents per bushel? $209.52. 3. What is the value of 796 pounds of tea at 96 cents per pound? ) $764.16. 4, What will 175 acres of land cost at 97 dollars per acre? $16975. 5. What is the value of 1234 bushels of wheat at 95 cents per bushel? $1172.30. 6. A nurseryman counted the trees in his orchard and found that he had 127 rows, each row containing 980 trees. How many trees were in the orchard? 124460 20 MULTIPLICATION. ALCIQOUGT PARTS; 54. Much Time can be saved when the multiplier is an aliquot part of some higher unit, by abbreviating the ordinary method as here illustrated. 55. 1. How many trees in 327 rows containing 25 trees to the row? 8175. PROCESS. 4)32700 S175 Expianation:—Multiply by 100 by annexing two ciphers, and then divide by 4. TABLE: Of 10 Of 100 Of 1000 14 is, 4:64 1s 4y5)1624---is- ae 185 ris kt 8k is eye O68 Shige ss y iss $y LOS RISP Wey tooe ess ae 24 is 4,123 is 4/125 is #32 3 is 4/162 is +4 | 1662 is + 5 is #¢/]20 is 4/250 is 4 62 is 2/25 is 4/ 3334 is 34 7% - is» 44334658 4 | 750 is 4 Bhar id 5S 00 isan ae | Os pe de ee 2. What will be the cost of 28 yards of cloth at 123 cents per yard? $3.50, MULTIPLICATION. 21 3. Find the cost of 256 yards of cloth at $1.064 per yard. $272. 4. What will be the cost of 258 cords of wood at $3.334 per cord? $860. 5. What will 176 bushels of corn cost at 374 cents per bushel? $66. 6. What will 192 bushels of wheat cost at $1.163 per bushel? $224. 7. What will be the cost of 48 yards of silk at $1.163 per yard? $56. 8. What is the value of 225 barrels of flour at $3.332 per barrel? $750. 9. What will 368 bushels of potatoes cost at 624 cents per bushel? $230. 10. What will be the cost of 324 pounds of tea at 75 cents per pound? $243. 11. What is the value of 216 bushels of apples at $1.374 per bushel? $297. 12. What will be the cost of 72 gallons of wine at $1.125 per gallon? $81. 13. When butter is worth 334 cents per pound, what will 786 pounds be worth? $262. NUMBERS ENDING WITH 5. 54. The following method of multiplying any two numbers whose Unit Figures are 5 will be found valuable. 55. 1. Multiply 45 by 25. 1125. PROCESS. 45 25 1125 ExpLanaTIon :—Multiply the figures in tens place to- 22 MULTIPLICATION. gether, increase this by half their sum, and to the result annex 25, or if the sum of the figures in tens place is odd, annex @5. 2. What cost 75 acres of land at 35 dollars per acre? $2625. 3. How many bushels of corn can be raised on 65 acres of land at the rate of 35 bushels per acre? 2275. 4, If 35 men can build a wall in 25 days, how many days will it take one man to build it? 875. 5. Ifit requires 125 tons of iron rail for one mile of railroad, how many tons will be required for 45 miles? | 5625, 6. A merchant bought 115 yards of cloth at 35 cents per yard. What did it cost? $40.25. 7. What will be the cost of 85 pounds of butter at 45 cents per pound? $38.25. NEWTON § MULTIPLICATION RULE. 38. This Valuable Method may be used in mul- tiplying any two numbers in which the unit figures add to TEN and the. other figures are ALIKE. 49. 1. Multiply 26 by 24. 624, PROCESS. 26 24 624 ExpLANAtion:—We say 4 times 6 are 24, put down both figures and carry 1 to the second figure of the mul- tiplier. Then say 3 times 2 are 6. Always carry ONE to the tens figure of the multiplier. The product of the MULTIPLICATION. 23 unit figures must occupy two places, hence, if their product is less than TEN, a cipher should be written in the product. 2. If aman travel 33 miles per day, how many miles will he travel in 28 days? 924. PROCESS. 33 28 924 Note:—The above rule is likewise applicable when. the digits of the multiplicand are auixe and the digits of the multiplier add to TEN, also when the complement of the unit figure in the multiplier cross-multiplied by the tens in the multiplicand is equal to the product of the other figures cross-multiplied. 3. What will 84 bushels of wheat cost at 86 cents per bushel? $72.24. 4. How many square rods in a field 147 rods long and 48 rods wide? 7056. 5. How man pounds of sugar are there in 126 packages, each package weighing 86 pounds. 10836. 6. How many bushels of wheat can be raised on 39 acres of land, if one acre produces 24 bushels? 936. 7. What will be the cost of 77 bushels of corn at 37 cents per bushel? $28.49. 8. What cost 64 bushels, of apples at 38 cents a bushel? $24.32. 9. A travels 30 miles a day, and B travels 38 miles a day. How many miles will both travel in 36 days? 2448, 10. How many sheets of paper in 26 quires, if there are 24 sheets in a quire? 624. 11. A mining company built 395 tenement houses at 24 MULTIPLICATION. an average cost of 395 dollars apiece. What did they all cost? : $156025. 12. A drover bought 42 oxen at 384 dollars a head. What did they cost? $1617. 13. What cost 29 pounds of coffee at 21 cents per pound? $6.09. 13. What is the value of 1574 yards of cloth at 48 cents per yard? £75.60. COMPEE MENU EMU DASE Ish ART Giarss 38. This rule is valuable when both multiplicand and multiplier are a Little Less than a unit of the next higher order. 39. 1. Multiply 96 by 94. 9024. PROCESS. 96-4 94 -6 90 24 ExpLanation:—Multiply the complements of both fac- tors together and write the result in the product. Then cross-subtract; that is, take the complement of one num- ber from the other number, and write the remainder at the left of the first product. If the product of the com- plements does not contain as many figures as the multi- plier, insert cipher to make up the deficit. 2. At 97 dollars per acre, what will a farm of 96 acres cost? $9312. 3. What will be the cost of 89 bushels of corn at 92 cents per bushel? $81.88. 4. Ifa planet travel 996 miles per minute, how far will it travel in 996 minutes? 99216. MULTIPLICATION. 25 5. What will 92 horses cost at 97 dollars per head? $8924. 6 How many square feet in a garden 93 feet long and 86 feet wide? 7998. 7. What will be the cost of 196 yards of cloth at 95 cents a yard? $186.20. 8. Ifa vessel sail 93 miles a day, how far will she sail in 98 days? 8649. 9. What will be the cost of 92 bushels of rye at 95 cents a bushel? $8740. 10. A has 99 dollars, and B has 61 times as much. How much has B? $6039. 11. How much will I receive for a farm of 95 acres at 48 dollars per acre? | $4560. 12. What must I pay for 990 town lots at an average price of 994 dollars? #98460. 13. How many square rods in a square field which measures 92 rods on each side? 8464. 14. < 64. Division is finding how many times one num- ber contains another. 65. The Dividend is the number to be divided. 66. The Divisor is the number by which we divide. 67. The Quotient is the result obtained by divis- ion. 68. The Remainder is the number which is some- times left after dividing. 69. The Sign of Division is +, and is read DIvID-— ED BY. Division is also indicated by writing the dividend above or at the right of the divisor, with a line between them. 70. Short Division is that in wich the steps in the solution are performed mentally. @i. Long Division is the method of dividing when all the work is written. @2. When a Remainder occurs at the end of divis- ion, it may be written over the divisor in the form of a fraction and annexed to the quotient. DIVISION. ; 31 73. When the Divisor is large, consider only the first two or three figures as a trial divisor, and compare them with the first two or three figures of dividend. @4. To Test the work, multiply the divisor by the quotient, and to the product add the remainder, if any. If the work is correct, the result will equal the dividend. FACTORING: @5. Frequently, when the divisor can be resolved in- to Factors, the work can be shortened by dividing by each of the factors in succession. If there is more than one remainder, the true remainder may be found by sub- tracting the product of the divisor and quotient from the dividend. @6. 1. Find the quotient of 594 divided by 18. 33. Expianation :— Divide the dividend by one factor of the divisor, the quotient by another, and so on tillall the factors are used. 2. In one hogshead there are 63 gallons. How many hogsheads in 15435 gallons? 245. 3. Ifa boat sail 24 miles an hour, how many hours will it be in sailing 1824 miles? 16, * 4. The product of two numbers is 26973; one of the numbers is 81; what is the other? aon. 5. A farmer raised 8288 bushels of wheat, averaging 56 bushels to the acre. How many acres did he plant. 148. 3:2 DIVISION. 6. A man bought 160 acres of land at 25 dollars an acre, giving in payment a house valued at 928 dollars, and horses at 96 dollars each. How many horses did he cive? 32. CR NG Es TIN Gee Deere @¢. This method often renders it quite easy to apply Short Divisiom to large numbers when there are ciphers at the right of the divisor. @%. 1. Divide 8765 by 600. 14; Rem. 365. PROCESS. 6 00)87 | 65 14 - 385 ExpLanation:—Cut off the ciphers at the right of the divisor, and the same number of places at the right of the dividend. Divide the remaining part of the dividend by the remaining part of the divisor, and prefix the re- mainder to the figures cut off for the true remainder. 2. If 120 acres of land cost 4080 dollars, what will one acre cost? $34. 3. A drover paid 28800 dollars for 360 horses. How much was that per head? $80. 4, Aman gave 5600 dollars for 160 acres of land. How much was that per acre? $35, 5. How many months musta person labor to earn 3430 dollars at 70 dollars per month? 49, - 6. Into how many lots of 40 acres each can a tract of land containing 6400 acres be divided? 160. 7. Two men start from the same place and travel in opposite directions, one at the rate of 23 miles a day, and the other at the rate 27 miles a day. When 4750 miles apart, how many days had they traveled? 95. a nf DIVISION. 33 ALIQUOT PARTS. 79. This method of division is the reverse of Multi- plication by aliquot parts, shown on page 20. $0. 1. Divide 450 by 25. | 18. PROCESS. 456 4 18(00 Expianation:—Multiply by 4 and then divide by 100, by cutting off two places. ' 2. At $1.25 per yard, how many yards of silk can be bought for 15 dollars? 12. 3. A dealer bought 25 horses for 2650 dollars. How much did he give a head? $106. 4. At 163 cents per yard, how many yards of muslin can be bought for 8 dollars? 48, 5. At 123 dollars per barrel, how many barrels of flour can be bought for 450 dollars? 36. 6. Ifaman can save 250 dollars per year, in how many years can he save 2250 dollars? J, If a locomotive run 25 miles an hour, how many hours will it be in running 1625 miles? 65. 8. If it takes 163 yards of silk to make a dress, how many dresses can be made from 450 yards? eer 9. How many weeks will it take a printer to earn 250 dollars, if he receives 162 dollars a week? 15. 10. A farmer received 14 dollars for a load of apples at 334 cents a bushel. How many bushels did he have? 42. 11. A farmer bought a tract of land for 2000 dollars. How many acres did he buy, if it cost him 123 dollars per acre? 160. . 34 DIVISION. 12. If the distance across the Atlantic ocean is 3000 miles, how many days will a vessel, sailing 125 miles per day, be in crossing? 24. COMPLEMENT DIVISION. $i. When the divisor is a Little Less than 100, 1000, ete., the following method will be found valuable. $2. Divide 2138672 by 98. 21823; Rem. 18. PROCESS. 21386 | 72 427 | 72 8 | 54 | 16 - 21823 | 14 brekie’ is Expianation:—Cut off from the right of the dividend, by a vertical line, as many figures as the divisor contains. Multiply the part on the left of the line by the comple- ment of the divisor and set the product under the divi- dend. Multiply the part of this product on the left of the line by the same multiplier and set down as_ before. Continue in like manner until no figure remains on the left of the line. Add theseveral results and forevery 1 carried across the line, add the number used as a multiplier. The part on the left of the line will be the quotient, and the part on the right, the remainder. Ifthe remain- der is equal to or larger than the divisor, carry one to quotient, and the excess will be the true remainder. This rule may be advantageously applied to many other numbers. To illustrate: If we wish to divide by 49 we may divide by 98 and multiply by 2, or if we wish er DIVISION. 35 to divide by 198, we may divide first by 99 and then that result by 2. 2. Divide 2326 by 32. 72; Rem. 22. PROCESS. 23 | 26 92 ExpLanation:—In this case we divide by 96, or three times the given divisor, which gives a quotient of 24. This multiplied by 3 gives 72, which is the true quoti- ent. 3. In one cask there are 94 gallons. How many casks. in 4230 gallons? 45, 4. Ifaship sail 99 miles a day, in how many days will it sail 12375 miles? 125. 5. In 240 quires of paper there are 5760 sheets. How many sheets in a quire? 24. 6. In one day there are 24 hours; how many days are there in 5200 hours? 216 da. 16 hr. 7. A man bought a drove of 95 horses for 4750 dollars. How much did he give apiece? $50. 8. Amansolda farm of 480 acres for 15360 dol- lars. How much did he get per acre? $32. 9. If aman can earn 998 dollars in a year, how many years will it take him to earn 15968 dollars? 16. 10. A farmer having 6272 dollars bought land at 32 dollars per acre. How many acres did he buy? 196. 11. A man wishes to invest 1645 dollars in railroad stock. How many shares can he buy at 47 dollars per share? 35. CANCELLATION. >< $3. Cancellation is the method of shortening computations by omitting common factors from both dividend and divisor. $4. Write the dividend on the right and the divisor - on the left of a verticaL LINE. Cancel all common fac- tors and divide the product ofthe remaining factors of the dividend by the product of the remaining factors of the divisor. $5. 0. 5. Five men share $11.56} equally. What is the share of each? $2.314. 6. Change % to an equivalent fraction having 24 for its denominator. oy. 7. Change #3 to an equivalent fraction expressed in its lowest terms. - 8. Change 4% to an equivalent fraction, having 9 for its denominator. 3 9. What will be the cost of 125 pounds of butter at 124 cents per pound? $1.564. 10. Ifa boy earn } of a dollar per day, how much can he earn in 12 days? $9. 11. A man owned a boat worth 2700 dollars. How much should he receive for ? of it? $1800. 12. A hunter shot 24 ducks one day, and } as many the next. How many did he shoot in both days? = 44. 46 COMMON FRACTIONS. 13. When wheat is selling at 3 of a dollar per bushel, how many bushels can be bought for 24 dollars? 30. l4. If from a bin containing 375% bushels of wheat, 2163 bushels are taken, how many bushels will remain? 159%. 15. James spent 4 of a dollar on Monday and 4 of a dollar on Tuesday. What part of a dollar did he spend both days? 3. 16. $329.7¢7\' 279104 29.04 Expianation:—In the contracted method the order of the figures of the multiplier is ReEveRseD and the unit figure written under the decimal of the multiplicand to be retained. Begin with the right hand figure of the multiplier to form partial products, dropping one figure of the multiplicand, as we multiply by each successive figure of the multiplier, making due allowance for the units arising from the product of the neglected figures, adding the nearest number of tens. Ciphers may be annexed to the multiplicand if necessary. 2. Multiply 123.215263 by 15.16, reserving two deci- mals in the product. 1867.94 DECIMALS. D1 CONTRACTED DIVISION. 146. Contracted Division of decimals is the re- verse of contracted multiplication. 147. 1 Divide 329.7727915 by 26.48352, retaining two decimals. 12.45. PROCESS. 2648 352)3829.77279 15 (12.45 264858 649 EXPLANATION: —In this case we see by inspection that the first two figures of the quotient will be whole numbers, and that four divisions must be made. Us- ing as many figures of the divisor as there are divisions to be made, we multiply by the first figure of the quo- tient, making due allowance for units arising from the product of it and the last omitted figure of the divisor. At each successive division omit one figure of the divisor, beginning at the right. 2. Divide 1867.94361727 by 123.215263, reserving two decimal places in the quotient. 15.16. iy. OF ILL LIB. PERCENTAGE. f4%. The Base is the number on which percentage is computed. 149. The Rate is the number which denotes how many hundredths are to be taken. 150. The Percentage is the product obtained by multiplying the base by the rate. 151. The Amount is the sum of the base and _per- centage. 152. The Difference is the difference between the base and percentage. 153. The Sign of Percentage is 4, and is read PER CENT. 154. The following Equations are adapted to the solution of all simple problems in percentage. FORMULAS. Percentage = Base x Rate. Rate = Percentage + Base. Base = Percentage + Rate. Amount = Base x (1 + Rate.) Difference = Base x (1 — Rate.) PERCENTAGE. 53 155. 1. A farmer who hada flock of 270 sheep, sold 334% of them. How many did he sell? 9). PROCESS. 3)270 90 Exputanation: Take sucha part of the given nuim- ber as the rate per cent is of 100. 2, What per cent is lost by selling cloth at 75 cents which cost 1 dollar? 25 3. What per cent is gained by selling cloth for 1 dol- lar which cost 75 cents? 334 4. A farmer having a flock of 250 sheep sold 20¢ of them. How many had he left? 200. 5. Bought corn at 50 cents a bushel. At what price must it be sold to gain 20 per cent.? $.60. 6. A farmer sold a horse for 75 dollars, which was at a loss of 25%. What was the cost of the horse? $100. 7. Bought cloth at 50 cents per yard and sold it at 60 cents per yard. What per cent did I gain? 20 8. A man sold a horse at a profit of 334%. If the horse cost him 120 dollars, what did he get for him? $160. 9, A farmer sold a horse for 100 dollars, which was at a gain of 257. What was the cost of the horse? SSO. 10. [send my agent 500 dollars to invest in goods. After deducting 3% commission how much will be invest- ed? $485. ll. By selling cloth at $4.50 per yard I lose 104. What will be my gain per cent, if I sell at 6 dollars per yard? 20. INTEREST. >< — 156. Interest is money charged for the use of money. 157. The Principal is the sum on which interest is counted. 158. The Amount is the sum of the principal and interest. 159. Simple Interest is counted on the prin- cipal only. 160. Compound Interest is interest on both principal and unpaid interest. 161. The old Cancellation Method of comput- ing interest is undoubtedly the best for general use. The following diagram is intended to illustrate how the terms should be arranged. FORMULA. ee Principal. ' ExpLaNnation:—We write the principal, rate per cent, —- 4 @ INTEREST. Dy» and number of days to run, on the right, and 860, orits factors, on the left. If the time is in months, write #2 only on the left. Point off two places in the result when the principal contains dollars only, and if it contain cents, point off two more. The operation may be shortened in various ways. Suppose the rate is 6 per cent, the result would be the same if we omit the rate from the right and write 60 only on the left. The divisor for any rate may be found by dividing 360 by the rate. In count- ing the time. regard 30 days as a month. 162. 1. Find the simple interest on 120 dollars for 1 month and 12 days, at &7. $1.12. STATEMENT. |1290 360 O08 | 42 2. Find the simple interest on 600 dollars for 24 days at 7 per cent. $2.80. 3. Find the simple interest on $36.84 for 5 months, at % per cent. #1.38. 4. What is the simple interest on 640 dollars for 21 days, at 6 per cent? $2.24. >). Find the simple interest on 720 dollars for 1 year, 4 months, 15 days, at 6 per cent. $59.40. 6. Find the simple interest on 2500 dollars for 7 months and 20 days, at 5 per cent. $79.86. 7. Find the simple interest on 6 dollars for 6 years, 6 months and 6 days, at 6 per cent. $2.35. 8. What will be the amount of 720 dollars for 20 days at 6 per cent, simple interest? $722.40. 9. Find the simple interest on 125 dollars for 1 year, 2 months and 12 days, at 6 per cent. $9. 10. Find the amount of $256.20 for 1 year, 3 months and 18 days, at 10 per cent, simple interest. $33.31. D6 INTEREST. 11. Find the amount of 200 dollars, for 2 years, at 6 per cent, compound interest, payable annually. $224.72. PARTIAL PAYMENTS: 163. Partial Payments made on notes, mort- gages and other interest-bearing certificates of indebted- ness are called INDORSEMENTS. 164. Nearly every Business Man has his own method of computing interest when partial payments have been made, and the subject has given rise to much litigation. We give only the method which has been adopted by the Supreme Court of the United States. UNITED: STATES METHOD: 165. Find the Amount of the principal to the time of the first payment, and subtract the payment for a new principal. If the payment is less than the interest, find the amount of the note to the time when the sum of the payments shall exceed the interest due. Subtract the sum of the payments and proceed as before. 166. This excellent Method is very simple. The only difculty occurs when the interest is greater than the payment. When this occurs, however, we can gener- ally see by inspection that the payment is not sufficient to discharge the interest,so that in such cases we may compute the amount at once up to the time when the sum paid is not less than the accrued interest, thus saving unnecessary work, by mentally estimating the in- terest in advance. INTEREST. 57 167. 1. A note for 150 dollars is dated June 12, 1888. Indorsed: October 12, 1889, 32 dollars; October What was $120.68. 12, 1790, $6.80; February 12, 1891, $21.60. due May 27, 1892, interest at 6 per cent? PROCESS. Days. i2 12 12 12 24 Years. Mon. ss - 6 - $9 10 90 10 91 - 2 - 92 _ | ee ca ; Paid. $32.00 It - 4 - 90 tt : 0 - Oo - eae Oo - 4 - 0 21.90 pa eae ek et ies (1° Pw) 150.00 12.00 Principal. Ent. lt yr. 4 mon. 162.00 32.00 Amount. Payment. 130.00 New Principal. 10.40 140.40 28.40 112.00 §.68 Int, l yr. 4 mon. Amount, Payment. New Principal. Int. lL yr. 3 m. 15 d. Balance due. ExpLanation:—Write the dates under each other, in 5S INTEREST. their regular order, subtract downward, and write the intervals beneath with the payments opposite. The first interval is 1 yr. 4 mon.; the interest on 150 dollars for this time is 12 dollars and the amount is 162 dollars; 162 dollars less 32 dollars is 130. dol- lars, the second principal. Consider mentally that the next interval of I year would afford about 8 dollars interest, which is more than the payment; hence we combine two intervals and their payments, making the time I yr. 4 mon. and the combined payment $28.40, which is enough to meet accrued interest. The amount of 130 dollars for I yr. 4 mon. is $140.40; $140.40 less $28.40 is L12 dol- lars, the third principal. The amount of 112 dollars for the last interval, I yr. $3 mon. 15 da. is $120.68, the balance due at date of settlement. 2. A note for 120) dollars is dated October 15, 1889, Indorsed: October 15, 1890, 1000 dollars; April 15, 1891, 200 dollars. How much remained due October 15, 1891. interest at 6 per cent? $82.56. 3. A note for 600 dollars is dated July 14, 1890. In- dorsed: May 26, 1891, $131,20; December 20, 1892, 40 dollars; September 14, 1893, 175 dollars. What was due July 14, 1894, interest at 6 per cent? $371.70. 4. A note for 850 dollars is dated January 1, 1892. Indorsed: July 1, 1892, $100.62; December 1, 1892, $15.28; August 13, 1893, $175.75. What was due on taking up the note January 1, 1894, interest at 6 per cent? | $650.39. 5. A note for 400 dollars is dated March 4, 1888. In- dorsed: September 4, 1888, 10 dollars; January 4, 1889, 30 dollars; July 4, 1889, 11 dollars; September 4, 1889, 80 dollars. What was due March 4, 1890, interest at 6 per cent? $313.33. INTEREST. 5Y 6. A note for 1750 dollars is dated November 23, 1892. Indorsed: November 26, 1894, 500 dollars; July 19, 1895, 50 dollars; September 2, 1895, 600 dollars, De- cember 29, 1895, 75 dollars. What was due February 11, 1896, interest at 7 per cent? $879.71. 7. A note for 2150 dollars is dated September 20, 1893. Indorsed: December 15, 1893, 75 dollars; February 4, 1894, 200 dollars; April 3, 1894, 150 dollars; July 1, 1894, 500 dollars: December 16, 1894, 1000 dollars. What was due March 20, 1895, interest at 8 per cent? $439.28, DISCOUNT. >< 168. Discount is a deduction made from a sum of money to be paid. 169. Commercial Discount is a deduction from the price of an article or from a _ bill without regard to time. 170. The Net Price is the list price less the dis- count. 17. 1. What is the net price of a parlor organ, listed at 300 dollars, with 50, 20, and 10 off? $108. PROCESS. 00 x .80 x .90 = .360600 x 300 = $108. ExpLanation:—When several discounts are allowed from list prices, subtract each from 100 and multiply the remainders and the list price together to find the selling price. . | 2. Find the value of a bill of goods amounting to 275 dollars at 5 per cent discount? $261.25. 3. What is the net price of a bill of hardware, listed at 80 dollars, with 25, 20, and 10 off? $43.20 4, If shoes marked $2.50 per pair are sold at 10 per cent discount, what is the net price? $2.50. DISCOUNT. 61 7. Sold county warrants amounting to 30 dollars at 5 per cent discount. What were the proceeds? $28.50. 10. A merchant receives 2% off for cash. How much does he save by discounting a bill of 240 dollars? $4.80. 5. What is the cash value of a bill of goods amount- ing to 500 dollars with 20 per cent discount, and 5 off for cash? $380. 8. Ifamerchant sell goods at the catalogue price from which he receives a discount of 20 per cent, what per cent does he make? 25. 6. A merchant buys goods at a discount of 20 per cent from list price and sells them at 20 per cent above the list price. What per cent does he make? 50. BANK DISCOUNT: 172. Bank Discount is simple interest, paid in advance, for three days more than the specified time. 173. The Proceeds of a note are the face of the note, less the discount. i174. The Maturity of a note occurs on the last day of grace, but if the last day of grace fall on Sunday or a legal holiday, the note matures on the preceding day. 1. What is the bank discount on $74.16 for 3 months, 18 days, at 5 per cent? $1.14. 2. What is the bank discount on 3860 dollars for 5 months, 8 days, at 6 per cent? $9.66. 8. Whatis the bank discount on 48 dollars for 4 months, 12 days, at 8 per cent? $1.44. 62 DISCOUNT. ERU EAD TSS@UNGE 175. True Discount is the difference between the face of a debt and its present worth. 176. The Present Worth of a debt, due at some future time without interest, is the sum which put at interest at the specified rate, will amount to the debt when it becomes due. 1L7¢@. To Find the present worth, divide the given sum by the amount of one dollar for the given time and rate. 1. When money is worth 6 per cent, what is the pres- ent worth of 1300 dollars, payable in 5 years? $1000. 2. Bought 2895 dollars worth of goods, on two year’s credit. What sum will pay the debt now, if money is worth 5 per cent? $2631.82. 3. Bought a house for $975.50, payable in 18 months without interest. How much will I gain by paying the debt now, money being worth,6 per cent? $80.55. 4. How much will I gainif instead of paying 5400 dollars cash for a piece of property, I pay 6000 dollars in 16 months, money being worth 9 per cent. 42.86. PROPORTION. 17s. Proportion is an equality of ratios. 179. Ratio is the relation of one number to another of the same kind. 180. The Extremes of a proportion are the first and fourth terms. 181i. The Means of a proportion are the second and third terms. 182. The Sign of Proportion is the double colon, ::, or the sign of equality, =. 183. Simple Proportion is employed for the solution of problems in which three quantities are given, so related that a fourth may be determined from them. 184. 1. If six menearn 75 dollars in a week, how much will 10 men earn in the same time? $125. PROCESS. mh) 6 10 ExpbLanation:—-Write the third term, or that number which is the same kind as the answer, on the right. When the result is to be larger than the third term, place the larger of the other two numbers on the right and the smaller on the left, but reverse this order when 64 PROPORTION. the result is to be less than the third term. Apply can- cellation and the result will be the required term. 2. If 12 yards of cloth cost 15 dollars, what will be the cost of 16 yards? $20. 3. if an ocean steamer sail 1820 miles in 5 days, how miles will she sail in 64 days? 2366. 4. If90 bushels of oats supply 40 horses 6 days, how many days will 450 bushels supply them? 30. 5. If 28 men mow a field of grain in 12 days, how many men will be required to mow it in 8 days? = 42. 6. Ifasum of money at interest produce 12 dollars in 4 years, how much will it produce in 7 years? $21. 7. If 24 bushels of wheat can be bought for 27 dol- lars, how many bushels can be bought for 45 dollars? 40, 8. If 20 bushels of wheat make 5 barrels of flour, how many bushels will it require to make 16 barrels? 64, 9. If65 bushels of potatoes can be raised on 24 acres of ground, how many bushels can be raised on 7 acres? 182. 10. If 35 head of cattle eat 36 acres of grass in a - month, how many cattle would 468 acres keep the same time. 455, 11. If 6 men can ean do a piece of work in 45 days, how many days will it take 15 men to do the same work? 18. 12. If it require 12 men to lay a certain number of bricks in 16 days, how many days will it take 8 men to lay the same number? 24. 13. The shadow of a certain tree measures 100 feet, while the shadow of a 4-foot stick measures 5 feet. What is the height of the tree? 80 ft. 14. If 18 bushels of wheat is bought for 24 dollars, and sold for 80 dollars, how much will be gained on 57 bushels, at the same rate of profit? $19. -PROPORTION. 65 15. If 20 men can perform a piece of work in 15 days, how many men must be added that the work may be performed in 4 of the time? 5, 16. If 4 of a bushel of peaches cost $0.52, what part of a bushel can be bought for $0.3? ts. 17. If butteris worth 18 cents per pound, and 36 pounds of sugar is exchanged for 30 pounds of butter, what is the price of the sugar per pound? $O.15. COMPOUND PROPORTION. 185. Compound Proportion is employed in the solution of problems in which the required term de- pends on a compound ratio. 186. In compound proportion, all the terms are in couplets or pairs of the same kind, except one. This is called the Odd Term, and is always the same kind as the answer. Each couplet should be considered sepa- rately in making the statement. 87. 1. If8men earn 40 dollars in 3 days, how much will 9 men earn in 4 days? $60. PROCESS. 40 8/9 ; 3 | 4 ExpLanation:—Use the vertical form of cancellation, writing the odd term on the right; then take the other numbers in pairs, or couplets of the same kind, and _ar- range them as in simple proportion. 2. If36 men earn 324 dollars in 18 days, how much will 42 men earn in27 days? $567. 3. If 12 horses plow 11 acres in 5 days, how many horses will plow 33 acres in 18 days? 10. 66 PROPORTION. 4. If6 men, in 10 days build a wall 20 feet long, 3 feet high, and 2 feet thick,in how many days can 15 men build a wall 80 feet long, 2 feet high, and 3 feet thick? 16. 5. Ifaman travel 130 miles in 3 days, when the days are 15 hours long, how many days will it take him to travel 390 miles, when the days are 9 hours long? 15. 6. If 12 men can mow 80 acres of grass in 6 days, how many days will it take 15 men to mow 200 acres? 12. 7. If6men can dig a trench 20 rods long, 6 feet deep, and 4 feet wide, in 16 days, working 9 hours per day, how many days will it take 24 men to dig a trench 200 rods long, 8 feet deep, and 6 feet wide, working 8 hours per day? 90, COMPOUND NUMBERS. a 188. Special rules are unnecessary for operations in Compound Numbers as the method is the same as the corresponding process in simple numbers, the only difference, being in their scales of increase. The student will readily understand the method of reduction upon examining the tables. AVOIRDUPOIS WEIGHT. 189. Avoirdupois Weight is used in weighing all coarse and heavy articles, as hay, grain, groceries, etc., and all metals except gold and silver. 190. The Avoirdupois Pound contains 7000 grains Troy, while the Troy pound contains 5760 grains. TABLE. T. LB. OZ. 1 2000 =. 32000 1 16 1, What cost 5 pounds of indigo at 10 cents per ounce? $8. 2. What cost 25 lb. 8 oz. of butter at 16 cents per pound? $4.08. 68 COMPOUND NUMBERS. 3. What cost 4500 pounds of hay at 6 dollars per ton? $13.50. 4, A horse weighs 1440 pounds Avoirdupois. How much would he weigh by Troy weight? 1750. TIME, 191. The Table given below is sufficiently accurate for ordinary business purposes. TABLE. YR. MON. DA. HR. 1 12 360 8760 1 30 720 1 24 1. I was born April 25, 1869. How old was I, July 14, 1890? 21 yr. 2 mon. 19 da. 2. The Declaration of Independence was written July 4, 1776. How many years had elapsed, March 1, 1860? 83 yr. 7 mon. 27 da. LONG MEASURE. 192. Long Measure is used in measuring lenghts and distances. TABLE. MI. RD. YD. FT. IN. if 320 1776 5280 63360 1 at 163 198 1 3 36 1 12 1. Reduce 264 ft. to rods. 16. 2. Reduce 2 mi. 2 rd. 2 ft. to feet. 10595, COMPOUND NUMBERS. 69 3. How many steps of 2 ft. 8 in. each will a man take in walking 2 miles? 3960. SURVEYOR S MEASURE. 193. Surveyor’s Weasure is used in measuring land, laying out roads, establishing boundaries, ete. 194. Surveyors use the Gunter’s Chain, which is 4 rods long and contains 100 links. TABLE. MI. CH. RD. LK. IN, ] 80 320 8000 63360 1 4 100 792 1 25 198 1 7.92 1. Reduce 400 links to rods. 16. 2. Reduce 128 rods to chains. 32. 3. Reduce 640 chains to miles. 8. 4. Reduce 3 ch. 25 links to rods. 1% SQUARE MEASURE 195. Square Measure is used in measuring sur- faces. TABLE. A. SQ. RD. SQ. YD. * --->SQ. FUE SQ. IN. 1 160 4840 43560 6272640 ] 305° 2724 39204 1 9 1296 1 144 70 COMPOUND NUMBERS. 1. Reduce 480 square rods to acres. 3. 2. Reduce 2560 square rods to acres. 16. 3. Express ~ of an acre in square rods. 60. 4. How many square feet in 27 square yards? 243. ». How many square feet in 1728 square inches? 12. 6. How many square yards in 4545 square feet? 505. 7. A gentleman divided his farm of 328 A. 74 sq. rd. equally among his 3 sons. What was the share of each? 109 A. 78 sq. rd. CUBIC MEASURE. 196. Cubic Measure is used in measuring solids. TABLE. CU. YD. CU. FT. CU. IN. 1 27 46656 1 1728 1. Reduce 20736 cubic inches to cubic feet. 12. 2. Reduce 482 cubic feet to cubic yards. 16. 3. Reduce 2 cu. yd. 2 cu. ft. to cubie inches. . 96768. DRY MEASURE. 197. Dry Measure is used for measuring grains, vegetables, fruits, ete. 198. The Standard Unit of dry measure is the bushel which contain 21502 cubic inches, or nearly 14 cubic feet. COMPOUND NUMBERS. 71 199. The Standard Gallon of the United States contains 231 cubie inches, or about -"s of a ecubie foot. The dry gallon contains 268% cubic inches. TABLE. BU. PK, GAL. QT. PT 1 4 8 3p 64 1 2 8 16 1 4 8 1 2 1. Reduce 448 pints to bushels. (ep 2. Reduce 1 bu. 1 pk. 1 gal. 1 qt. 1 pt. to pints. 91. 200. The weight of a Bushel of various articles is given in the following TABLE. ARTICLES. ILB ARTICLES, LB. | Apples 50 Hair, unwashed | 8 Barley 48) Hemp seed 44 | Beans 60 Hungarian seed 45 | Bluegrass seed 14) Lime 80 Bran 20, Millet 45 Buckwheat 52) Oats 132 Castor beans 46) Onions 157 Charcoal 22|| Onion sets ~~ =—«(14 Clover seed 60}, Potatoes 60 Coal 80), Potatoes, sweet 50 | Corn 56|| Rye 56 Corn, in ear 70), Salt 50 Corn meal 50) Timothy seed 45 | Flax seed 56 Turnips 56 | Hair, washed 4|| Wheat 60 1. How many bushels of corn in a load weighing 1344 pounds? 24. 2. How many bushelsin a load of wheat weighing 1290 pounds? 214. Lo COMPOUND NUMBERS. 3. How much’should I receive for 1536 pounds of oats at 20 cents per bushel? ~ $9.60. 4. Bought 12 gallons of syrup at 75 cents a gallon, and sold it at 24 cents a quart. How much did I gain? $2.52. 5. At $2.40 per bushel what should I receive for a load of timothy seed weighing 2271 pounds, deducting the weight of the wagon, 1236 pounds? $55.20. MISCELLANEOUS TABLE. 4 Inches, 1 Shingle. 4 Inches, 1 Hand. 6 Feet, Ll Fathom. 3 Miles, 1 Weague. 4 Gills, LEP ing 5 Bushels corn, 1 Barrel. 60 Seconds, 1 Minute. 60 Minutes, 1 Hour. 16 Drams, 1 Ounce. 24 Sheets, 1 Quire. 20 Quires, 1 Ream. 12 Things, 1 Dozen. 12 Dozen, 1 Gross. 20 Things, 1 Score. 15° Longitude, 1 Hour. 100 lb. Grain, 1 Cental. 100 lb. Fish, 1 Quintal. 196 lb, Flour, 1 Barrel. 200 Ib. Beef or pork, 1 Barrel. 280 lb. Salt, 1 Barrel. 39.37 Inches, 1 Meter. 4.8665 Dollars, 1 £ Sterling. INVOLUTION. 202. Involution is the process of raising a num- ber to any given power. 203. A Power is the product arising from multi- plying a number by itself in continued multiplication. 204. The First Power of a number is the number itself. 205. The Second Power of a number is called its SQUARE. 206. The Third Power of a number is called its CUBE. 207. The Degree of a power is indicated by an exponent, which is a small figure placed a little above and at the right of the number. Thus, 3*, indicates the fourth power of 3. 208. The Product of any two or more powers is the power denoted by the sum of their exponents. Hence if we multiply the third power of a number by the fourth power the product will be the seventh. 209. 1. What is the fourth power of 3? 81. PROCESS. $3x3x3xS=SL. ExpLanation:—Multiply the number successively by 74 INVOLUTION. itself till it has been taken as many times as a factor as there are units in the exponent of the required power. 2, What is the square of 16? 256. 3. What is the cube of 9? 729. 4. What is the fourth power of 5? 625. 5. What is the fifth power of 6? RiA0; NUMBERS ENDING WITH «3. 210. The following method of squaring a number whose Unit Figure is 5 will be found valuable. 211° 1. What is the square of 25? 625. PROCESS. 25 20 625 Expianation:—Multiply the part preceding 53 by itself increased by I and prefix the result to 25. 2. What is the square of 75? 5625, 3. What is the square of 35? 1225. 4. What is the square of 45? 2025. >. What is the square of 195? 38025. 6. What is the square of 115? 13225. 7. What is the square of 995? 990025. ENTE GWE 2's: 212. The Square of numbers ending with 25 may —~l A INVOLUTION. be readily written out by the method explained below. 213. 1. What is the square of 625? 390625, PROCESS. 39 0625 ExpLaNnaTion:—Square the part preceding 25, add half the same part to the result, discarding fractions, and annex 0625, or if the part preceding 25 is odd, annex 3625. 2. What is the square of-425? 180625. 3. What is the square of 925? 855625. 4. What is the square of 325? 105625. 5. What is the square of 1025? 1050625. MIXED NUMBERS. 214. The method of squaring Mixed Numbers ending with 4 is illustrated below. 215. 1. Find the square of 63. 42 vol PROCESS. 6 62 A424 ExpLaNnaTion:—We say @ times 6 are 42 and annex 4 to the product. Always add 1 tothe multiplier. This method is applicable in all problems like the above. The student should study the method and apply the same principle to other fractions. 2. Find the square of 73. d64. 3. Find the square of 93 905. 4. Find the square of 113. 1324, 76 INVOLUTION. 5. Find the square of 493. 24504. 6. What cost 123 pounds of butter at 123 cents per pound? $1564. SOU ARE-OF PW @SDIGI Ts SE ie. 216. Small Numbers may be squared mentally, by the following simple method. 217. 1 What is the square of 18? 324. PROCESS. 16 x 20+4= 324 Expianation:—Take the product of two numbers, one of which is as much less than the number to be squared as the other is greater, and one of the numbers a multiple of ten, and add the square of the difference between the givén number and one of the asumed num- bers. 2. What is the square of 27? 729, 3. What is the square of 21? | 441, 4, What is the square of 33? 1089. ». What is the square of 79? 6241. DOU ATs DOLE NT IN Bis 218. The Square of any number of nInES may be written out without multiplying. 219. 1. What is the square of 999? 998001. PROCESS. 998001 EXPLANATION :—Erase one 9 from the left of the num- > ae bi Ree i i 2 ae ed 8 a) A ~ < “ber to be Re a wtinted annex an $8, as many ciphers as there e nines, anda I. ; 2. Find the square of 9. 81. 3. Find the square of 99. 9801. 4. Find the Square of 9999. 99980001. " INVOLUTION. | 77 ie y : poe aa se EVOLUTION. 220. Evolution is the process of finding roots of numbers. 221. A Root of a number is one of its equal fac- tors. 222. The Sign of Evolution, \, is a modification of the script letter r. Roots are also indicated by frac- tional exponents. 223. The following table of Squares and Cubes should be learned by the pupil. A Maylide Numbers 1, 2, 3, 4 5, 6, 4) othe Squares I, 4, 9, 16, 25, 36, 49, 64, SI. subes 1, 8, 27, 64, 125, 216, 343, 512,729. 224. It will be observed that Square Numbers never end in 2, 3, 7, or 8, and that the cubes of no two digits end with the same figure. Hence, in finding the eube root of perfect cubes, we can easily determine the unit figure of the root from the unit figure of the power. ———— cle en SS aS ns eS OTS Ee eee EVOLUTION. 79 EVOLUTION BY FACTORING. 225. To find Any Root of a perfect power, resolve the number into its prime factors, and for the square roct take one of two equal factors, for the cube root * take one of three equal factors, ete. 226. 1. What is the square root of 225? 15. PROCESS. 225 =—-383x3xkK3x5 225 = $8 X53 = 15 2. Find the square root of 625. 25. 3. Find the square root of 1296. 36. 4. Find the cube root of 1728. 12. 5. Find the fourth root of 1296. 6. 6. Find the fifth root of 243. 3 SOUARE ROOT BY ANALYSIS. 227. Separate into periods of two figures each, beginning at the right. The first figure is the root of the greatest square in the left hand period. Subtract its square from the first period, and bring down the next period. Double the root found and divide, disre- garding the right hand figure of the dividend, and place the result in the root and at the right of the divisor. Multiply the complete divisor by the last figure of the root and proceed as before. If a cipher occur in the . root, annex a cipher also to the trial divisor and bring down the next period. 80 EVOLUTION. 228. 1. What is the square root of 1296? 36. PROCESS. 12.96(36 66 396 396 2. What is the square root of 2304. 48, 3. The area of asquare field is 6561 square rods. How many rods in length or breadth? 81. 4, A man has a square field containing 4096 square rods. How many rods in length or breadth? 64. 5. The length of a rectangular field containing 20° acres is twice its width? What is the distance around it? 240 rd. 6. A square field measures 6 rods on each side. What is the length of the side of a square field which is 16 times as large? 24 rd. 7. If it costs $572 to enclose a field 72 rods long and 32 rods wide, how much less will it cost to enclose a square farm of equal area with the same kind of fence? SIMILAR SURFACES. 229. Similar Surfaces are to each other as the squares of their like dimensions. 230. Like Dimensions of similar surfaces are to each other as the square roots of their areas. 231. 1. A hole made by a 2 inch auger bit, is how many times as large as one made by an inch auger bit? 4, EVOLUTION. 81 Cal 2. If the area of a circle, whose diameter is 7 feet is 38.5 sq. ft., what will be the area of a circle 21 feet in diameter. 346.5 sq. ft. 3. A rectangular field is 12 rods wide and 20 rods long. What must be the width of a road across one end and one side to contain 4 the area of the entire field? 2 rd. 4. If one side of a triangle is 12 feet, and its area is 36 square feet, how many square feet in the area of a similar triangle, the corresponding side of which is 8 feet? 16. 5. The area of a triangle, the length of whose base is 8 rods, is 92 square rods. How many square rods are there in the area of a similar triangle, the corresponding side of which is 4 rods? 13. Cay Bs ROOTBY INSPECTION: 232. The Cube Root of perfect cubes of not more than six figures can be easily found by inspection. 233. 1. Find the cube root of 15625. 25. PROCESS. ( 15,625 )* = 25 ExpLaNnation :—-For the first figure of the root, we write the root of the greatest cube in the left hand _ period, which is 2, and then by inspection, or reference to the table, we see at once that the other figure of the root must be 5, as the cube of no other digit ends with 5. 2. Find the cube root of 1728. 12. 3. Find the cube root of 12167. 23. 4. Find the cube root of 39304. 34. 5. Find the cube root of 91125. 45. 82 EVOLUTION. 5. Find the cube root of 175616. 56. 6. Find the cube root of 300763. 67. 7. Find the cube root of 474552. 78. 8. Find the cube root of 704969. 89. 9, Find the cube root of 753571. 91. CUBE; RG) Ochs bY aac eas less 234. Separate into periods of three figures each. The first figure is the root of the greatest cube in the left hand period. Subtract the cube and bring down the next period. Square the root found, multiply by 300, and divide to find the second figure of the root. To three times the first figure of the root, annex the last. Multi- ply this factor by the last root figure and add the result to the trial divisor. Multiply the complete divisor by the last figure of the root, subtract and proceed as_be- fore. When the dividend will not contain the trial divi- sor, write a cipher in the root and two at the right of the trial divisor. 235. 1. What is the cube root of 13824? 24. PROCESS. ) 13,824(24 ‘s 1200 3824 256 F 1456 5824 2. What is the cube root of 74088? 42. 8. What is the side of a cubical box which contains 873248 solid inches? 6 ft. EVOLUTION. 83 4. What is the depth of a cubical bin whose contents are 79507 cubic feet? 43 ft. 5. What is the length of the side of a cubical box that contains 15625 cubic feet? 25 ft. 6. What is the side of a cube equal to a pile of wood 81 feet long, 27 feet wide and 9 feet high? 27 it. SIMILAR SOLIDS. 236. The Contents of similar solids are to each other as the cubes of their like dimensions. 237. Like Dimensions of similar solids are to each other as the cube roots of their contents. 238. The Side of a cube, whose solidity bears a giv- en relation to that of a cube whose side is given, is found by eubing the given side, multiplying the result by the given proportion and extracting the cube root of the product. 239. 1. What is the side of a cubical vat which contains } as much as one whose side is 6 feet? 3 ft. 2. Ifa cubic inch of gold is worth 200 dollars, what is the worth of a cube of gold whose side is 3 inches? ) $5400. 3. Ifa cubical block of granite, whose side is 4 inches weigh 12 pounds, what will a cubic foot of the same gran- ite weigh? 324 Ib. 4, I have a cubical box whose side is 3 feet. I want another which will contain 8 times as much. What will be the length of its side? 6 ft. 5. Ifacannon ball 8 inches in diameter weigh 40 pounds, what is the weight of one of the same metal, whose diameter is 4 inches? 5 Ib. MENSURATION. 240. For the practical convenience of those who have occasion to refer to Mensuration, we give the follow- ing principles, covering the whole ground of practical geometry. PRINCIPLES. 241. The Diagonal of a square is equal tothe side of the square multiplied by 1.414. 242. The area of a Triangle is equal to half the product of the base by the altitude. 2438. The side of an Inscribed Square is equal to the diameter multiplied by .7071. 244. The area of any Parllelogram is San to the product of the base by the altitude. 245. The areaof a Parabola is equal to the base multiplied by two-thirds of the altitude. 246. The area of an Ellipse is equal to the product of the two diameters multiplied by .7854. 247. The contents of a Sphere is equal to the cube of the diameter multiplied by .5236. MENSURATION. 85 248. The contents of a Wedge is equal to the area of the base multiplied by half the altitude. 249. The surface of a Sphere is equal to the square of the diameter multiplied by 3.1416. 250. The area of a Sector of a circle is equal to the length of the are multiplied by half the radius. 251. The area of a Trapezoid is equal to its alti- tude multiplied by half the sum of its parallel sides. 252. The side of an Imnseribed Equilateral Triangle is equal tothe diameter multiplied by .866025, 253. The contents of a Cylinder or Prism is equal to the area of the base multiplied by the altitude. 254. The contents of' a Pyramid or Cone is equal to the area of the base multiplied by one-third of the altitude. 255. The convex surface of a Pyramid or Cone is equal to the perimeter of the base multiplied by half the slant height. 256. The entire surtace of a Cylinder or Prism is equal to the area of both ends plus the product of the length by the periphery. 257. The side of a Cube which may be cut from a given sphere is equal to the square root of one-third of the square of the diameter. 258. The diameter of a Cirele that shall contain the area of a given square is equal to the side of the square multiplied by 1.1284. 259. The area of any Regular Polygon is equal to the perimeter multiplied by half the perpendicular distance from the center to one of the sides, 86 MENSURATION. 260. The convex surface of a Frustrum of a pyra- mid or cone is equal to the sum of the perimeter of the two bases multiplied by half the slant height. 261. The area of a Trapeziumi is equal to the di- agonal multiplied by half the sum of the perpendiculars drawn from the vertices of the opposite angles to the diagonal. 262. The Ratio betewen the diameter and circum- ference of a circle, expressed decimally and the approxi- mation carried to thirty places. is 3.14159265358979323846 264338328, 263. The area of a Segment ofa circle is equal to the area of a corresponding sector less the area of the tri- angie, or plus the area of the triangle when the segment is greater than a semicircle. 264. The side ofa Square that will contain the area of a given circle is equal to the square root of the area, or the diameter multiplied by .8862, or the circum- ference multiplied by .2821. 265. The contents of a Frustrum of a pyramid or cone is equal to the sum of the areas of the two ends plus the square root of the product of these areas, multi- plied by one-third of the altitude. RECTANGISES. 266. A Rectangle is a figure that has four straight sides and four right angles. 267. The Area of a rectangle is equal to the pro- duct of its length by its breadth. MENSURATION. 87 268. 1 At 12 cents a square yard, what will it cost to paint the walls of two rooms, each 16 feet square and 9 feet high? ~ $15.36. STATEMENT. | 128 9/9 12 ExpLanation:—-Multiply the entire distance around the rooms by the height, divide by 9 to reduce to square yards, and multiply by the price per yard. 2. How many square feet in a floor 16 feet long and 14 feet wide? 224. 3. How many acres in a field of land 96 rods long and 80 rods wide. 48, 4. Ifa floor is 12 feet long, how wide must it be to contain 132 square feet? 11 ft. 5. Find the difference between a floor 20 feet square, and two others 10 feet square. 200 sq. ft. 6. One side of a rectangular field containing 63 acres is 120 rods. What is the other? 84 rd. 7. How many yards of carpet 13 yards wide will cover a floor 18 feet long, 15 feet wide? 20 yd. 8. At 10centsa square yard, what will it cost to plaster the walls and ceilings of three rooms, each 15 ft. 6 in. long, 13 ft. 8 in. wide and 12 ft. high? $44.51. PE tAN GPS, 269. A Triangle is a figure which has three an- gles and three sides. 270. A Right Angle is the angle formed when one line is drawn perpendicular to another. 271. The Hypotenuse of aright angled triangle is the side opposite the right angle. 88 MENSURATION.. 272. The Base of a triangle is the side on which it is assumed to stand. 273. The Perpendicular is the side which forms a right angle with the base. 274. The Area ofa triangle is equal to half the product of the base by the altitude. 275. The Hypotenuse of aright angled triangle, is equal the square root of the sum of the squares of the other two sides. 276. The Base or Perpendicular is equal to the square root of the difference of the squares of the hypotenuse and the other side. It is also equal to the square root of the product of the sum and difference of the hypotenuse and the other side. 2@¢@. 1. What is the area of a triangle whose base is 16 feet and whose altitude is 13 feet? 96 sq. ft. 2. ‘The base of a right angled triangle is 40 feet, and the perpendicular is 30 feet. What is the eb aor 5 3. The hypotenuse of a right angled triangle is 73 feet and the perpendicular is 43 feet. What is the base? 6 ft. 4, The base of a right angled triangle is 34 feet and the hypotenuse is 123 feet. What is the perpendicular? ies 5. A rectangular field is 60 rods long and 45 rods wide. What is the distance between two opposite corn- ers? 75 rd. 6. What is the area of a triangular piece of ground whose base is 40 rods, and whose perpendicular height is 28 rods? 3d A. 7. A pole is 27 feet high. How many feet above the ground must it be broken in order that the upper part, clinging to the stump, may touch the ground 9 feet from the base? 12. MENSURATION. 89 8. The main mast of a vessel .is 72 feet high. How many feet above deck must it be broken in order that the upper part, clinging to the stump, may touch the deck 16 feet from the base? 342, CLERC lakes. 278. A Cirele is a plane figure bounded by a curved line, every part of which is equally distant from a point within, called the center. 279. The Circumferenee is the line which bounds the circle. 280. The Radius of a circle is a straight line drawn from the center to the circumference. 281. The Diameter ofa circle is a straight line drawn through the center, and terminated by the cir- cumference. 282. The Circumference of a circle is equal to the diameter multiplied by 3+. Hence, the diameter is equal to the cireumference divided by 3+. 283. The Area ofa circle is equal to the cireumfer- ence multiplied by one-fourth the diameter; or, the square of the diameter multiplied by +44. 284. 1. Whatisthe circumference of a cirele 28 inches in diameter? 88 in. STATEMENT. | 28 7\|22 EXPLANATION: Simply multiply by 3+, by reducing it to an improper fraction and applying cancellation. 2. What is the circumference of a log 14 inches in diameter? 3 ft. 8 in. 3. How far is it around a circular pond that is 45 feet in diameter? 1413 ft. 90 MFNSURATION. 4. What is the area of a circle 14 feet in diameter? 154 sq. ft. 5. What is the radius of a circle whose circumference is 616 feet? 98 ft. 6. What is the area of a circular pond 70 rods in circumference? 3850 sq. rd. 7. What is the diameter of a circle whose circumfer- ence is 154 feet? 49 ft. LUMBER MEASURE. 285. To measure Lumber, multiply the width in inches, the thickness in inches, and the length in feet together, and divide the product by 12. 286. To find the quantity of lumber in a Leg, mul- tiply the square of the diameter in inches at the small end by the length in feet, and divide the product by 24. 28¢. Whena board Tapers uniformly in width, find the average by taking half the sum of the two ends. If it taper also in thickness, the contents in board feet may be found by multiplying the sum of the areas of the two ends in square inches by the length in feet, and dividing the product by 24. FORMULA. No. Pieces. Te OO atte % Mc Length. | Width. Thickness. MENSURATION. 9] 288. 1. How many feet in 3 pieces 2 x 4, 16 feet long? 32. STATEMENT. | 33 2 4 4 —«G ExpLanation:—Write the given dimensions on the right and the factors of 12 on the left. The price per foot should also be written on the right when the cost is required. 2. How many feet in 11 pieces 6 X 8, 14 feet long? 616. 3. How many feet in 16 boards 10 inches wide and 12 feet long? 160. 4. How many feet of lumber in a log 15 inches in diameter and 16 feet long? 150. 5. How many board feet in a post 3 x 4 at one end, 4 x 6 at the other, and 10 feet long? 15. 6. How many feet in 56 fence posts 2 x 4 at one end, and 4 x 4 at the other, and 8 feet long? ° 448, 7. What will it cost to floor a room 14 by 20 with 2 dollar flooring, allowing + for matching? $6.72. 8.