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MATHEMATICS LISRARY
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THE SCIENCE
OF
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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.
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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.