Page images
PDF
EPUB

by 96.

2. Multiply 31704592 by 36. Ans. 1141365312. 3. Multiply 29753804 by 72. Ans. 2142273888. 4. Multiply 7128368

Ans. 684323328. 5. Multiply 160430800 by 108. Ans. 17326526400. 6. Multiply 61835720 by 1320. Ans. 81623150400.

7. There was an army composed of 104 * battalions, each consisting of 500 men ; what was the number of men contained in the whole ?

Ans, 52000. 8. A convoy of ammunition bread, consisting of 250 waggons, and each waggon containing 320 loaves, having been intercepted and taken by the enemy, what is the number of loaves lost?

Ans. 80000.

OF DIVISION.

Division is a kind of compendious method of Subtraction, teaching to find how often one number is contained in another, or may be taken out of it: which is the same thing.

The number to be divided is called the Dividend.-The number to-divide by, is the Divisor.–And the number of times the dividend contains the divisor, is called the Quotient.Sometimes there is a Remainder left, after the division is finished.

The usual manner of placing the terms, is, the dividend in the middle, having the divisor on the left hand, and the

quotient on the right, each separated by a curve line; as, to divide 12 by 4, the quotient is 3, Dividend

12 Divisor 4)

(3 Quotient;

4 subtr. showing that the number 4 is 3 times contained in 12, or may be 3 times 8 subtracted out of it, as in the margin. 4 subtr.

| Rule-Having placed the divisor before the dividend, as above directed, find how often the divisor is con- 4 subtr. tained in as many figures of the divi. dend as are just necessary, and place the number on the right in the quotient.

Mul.

12

4

A battalion is a body of foot, consisting of 500, or 600, or 700 men, more or less. + The ammunition bread, is that which is provided for, and distributed to the soldiers; the usual allowance being a loaf of 6 pounds to every soldier, once in 4 days. 1 In this way the dividend is resolved into parts, and by trial is found how often

the

Multiply the divisor by this number, and set the product under the figures of the dividend before-mentioned.–Subtract this product from that part of the dividend under which it stands, and bring down the next figure of the dividend, or more if necessary, to join on the right of the remainder - Divide this number, so increased, in the same manner as before ; and so on till all the figures are brought down and used.

N. B. If it be necessary to bring down more figures than one to any remainder, in order to make it as large as the divisor, or larger, a cipher must be set in the quotient for every figure so brought down more than one.

TO PROVE DIVISION.

* Multiply the quotient by the divisor ; to this product add the remainder, if there be any , then the sum will be equal to the dividend when the work is right.

the divisor is contained in each of those parts, one after another, arranging the several figures of the quotient one after another, into one nuinber.

When there is no remainder to a division, the quotient is the whole and perfect answer to the question. But when there is a remainder, it goes so much towards another time, as it approaches to the divisor; so, if the remainder be half the divisor, it will go the half of a time more;

if the 4th part of the divisor, it will go one fourth of a time more ; and so on. Therefore, to complete the quotient, set the remainder at the end of it, above a small line, and the divisor below it, thus forming a fractional part of the whole quotient.

* This method of proof is plain enough; for since the quotient is the number of times the dividend contains the divisor, the quotient multiplied by the divisor must evidently be equal to the dividend.

There are also several other methods sometimes used for proving Division, some of the most useful of which are as follow :

Second Method—Subtract the remainder from the dividend; and divide what is left by the quotient; so shall the new quotient from this last division be equal to the former divisor, when the work is right.

Third MethodAdd together the remainder and all the products of the several quotient figures by the divisor, according to the order in which they stand in the work; and the sun will be equal to the dividend when the work is right.

EXAM.

[merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]

3. Divide 73146085 by 4. Ans. 182865211 4. Divide 5317986027 by 7. Ans. 7597122894. 5. Divide 570196382 by 12. Ans. 4751636571. 6. Divide 74638105 by 37. Ans. 2017246.1. 7. Divide 137896254 by 97. Ans. 142161084 8. Divide 35821649 by 764.

Ans. 4688674 9. Divide 72091365 by 5201.

Ans. 1386132T: 10. Divide 4637064283 by 57606.

Ans. 80496 1787. 11. Suppose 471 men are formed into ranks of three deep, what is the number in each rank!

Ans. 157. 12. A party at the distance of 378 miles from the head quarters, receive orders to join the corps in 18 days : what number of miles must they march each day to obey their orders ?

Ans. 21. 13. The annual revenue of a gentleman being 383301 ; how much per day is that equivalent to, there being 365 days in the year?

Ans. 1041.

CONTRACTIONS IN DIVISION. There are certain contractions in Division, by which the operation in particular cases may be performed in a shorter manner, as follows :

1. Divi

1. Division by any Small Number, not greater than 12, may be expeditiously performed, by multiplying and subtracting mentally, omitting to set down the work, except only the quotient immediately below the dividend.

[blocks in formation]

II. * When Ciphers are annexed to the Divisor; cut off those ciphers from it, and cut off the same number of figures from the right-band of the dividend ; then divide with the remaining figures, as usual. And if there be any thing remaining after this division, place the figures cut off from the dividend to the right of it, and the whole will be the true remainder i otherwise, the figures cut off only will be the remainder.

EXAMPLES 1. Divide 3704196 by 20. 2. Divide 31086901 by 7100. 2,0).370419,6

71,00) 310869,01 (437871:..

284
Quot. 185209 35

268
213

556
497

599
568

31

3. Divide

* This method is only to avoid a needless repetition of ciphers which would happen in the common way. And the truth of the principle on which it is

founded 7x8 56

09

3800

3. Divide 7380964 by 23000.

Ans. 320582 4. Divide 2304109 by 5800.

Aps. 397 150 III. When the Divisor is the exact Product of two or more of the small Numbers not greater than 12 : * Divide by each of those numbers separately, instead of the whole divisor at

once.

N. R. There are commonly several remainders in working by this rule, one to each division ; and to find the true or whole remainder, the same as if the division had been performed all at once, proceed as follows: Multiply the last remainder by the preceding divisor, or last but one, and to the product add the preceding remainder ; multiply this sum by the next preceding divisor, and to the product add the next preceding remainder; and so on, till you have gone backward through all the divisors and remainders to the first. As in the example following:

EXAMPLES.

1. Divide 31046835 by 56, or 7 times 8. 7) 31046835

6 the last rem.

mult. 7 preced. divisor. 8) 4435262-1 first rem.

42
554407 – 6 second rem. add 1 the 1st rem.

Ans. 55440743

43 whole rem.

2. Divide 7014596 by 72.
3. Divide 5130652 by 132.
4. Divide 83016572 by 240.

Ans. 9742441.
Ans. 38868, 13.
Ans. 34590271%.

2

founded is evident: for cutting off the same number of ciphers, or figures, from each, is the same as dividing each of them by 10, or 100, or 1000, &c. accord. ing to the number of ciphers cut off; and it is evident, that as often as the whole divisor is contained in the whole dividend, so often must any part of the former be contained in a like part of the latter.

* This follows from the second contraction in Multiplication, being only the converse of it; for the half of the third part of any thing, is evidently the same as the sixth part of the whole; and so of any other numbers. The reason of the method of finding the whole remainder from the several particular ones, will best appear from the nature of Vulgar fractions. Thus in the first example above, the first remainder being 1, when the divisor is 7, makes this must be added to the second remainder, 6, making 6 to the divisor 8,or to be divided by But 6436 X 7+1 43

43 ; and this divided by 8, gives.

43 7 7

8.

[ocr errors]

IV. Common

« PreviousContinue »