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§ 32. Long Division, or when the divisor contains several figures.

RULE.

I. Set down the divisor on the left of the dividend, draw a curved line between them, and also a curved line on the right of the dividend.

II. Note the fewest figures of the dividend, counted from the left hand, that will contain the divisor; find how often they contain it, and set the figure in the quotient.

III. Multiply the whole divisor by this figure; set the product under the first figures of the dividend, and subtract it from them.

IV. To the remainder annex the next figure of the dividend, then find how often the divisor is contained in this new number, and set the figure in the quotient.

V. Multiply the whole divisor by the last figure of the quotient, and subtract the product from the last number containing the divisor. To the remainder annex the next figure of the dividend, and find the figures of the quotient in the same way, till all the figures of the dividend are brought down.

NOTE 1. There are four numbers in division. First, the dividend; second, the divisor; third, the quotient; fourth the remainder.

NOTE 2. There are five operations in division. First, to write down the numbers; second, find how many times: third, multiply; fourth, subtract; fifth, bring down.

Q. How do you set down the numbers for division? What do you do next? What do you do next? What is the next step? How many numbers are there in division? What are they? operations are there in division? Name them.

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How many

EXAMPLES.

1. Divide 11772 by 327.

Having set down the divisor on the left of the dividend, it is seen that 327 is not contained in 117; but by observing that 3 is contained in 11, 3 times and something over, we conclude that the divisor is contained at least 3 times in the first four figures of the dividend.

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1962

1962

0000

Set down the 3 in the quotient, and multiply the divisor by it; we thus get 981 which being less than 1177, the tient figure is not too great: we subtract 981 from the first four figures of the dividend, and find a remainder 196, which being less than the divisor, the quotient figure is not too small. Annex to this remainder the next figure 2, of the dividend.

As 3 is contained in 19, 6 times, we conclude that the divisor is contained in 1962 as many as 6 times. Setting down 6 in the quotient and multiplying the divisor by it, we find the product to be 1962. Therefore the entire quotient is 36, or the divisor is contained 36 times in the dividend.

NOTE 1. After multiplying by the quotient figure, if any one of the products is greater than the number supposed to contain the divisor, the quotient figure is too large, and must be diminished.

NOTE 2. When any one of the remainders is greater than the divisor, the quotient figure is too small, and must be increased by at least 1.

Q. If any one of the products is too large, what do you do? If any one of the remainders is greater than the divisor, what do you do? 2. Divide 2756 by 26.

We first say, 26 in 27 once, and place 1 in the quotient. Multiplying by 1, subtracting, and bringing down the 5, we say 26 in 15, 0 times, and place the 0 in the quotient. Bringing down the 6, we find that the divisor is contained in 156, 6 times.

OPERATION.

26)2756(106

26

156

156

NOTE. If after having annexed the figure from the dividend to any one of the remainders, the number is less than the divisor, the quotient, figure is 0, which being written in the quotient, annex the next figure of the dividend and divide as before.

DEMONSTRATION OF THE RULE OF DIVISION.

$33. If 6 simple units be divided by 3, the quotient will be 2. If 6 units of the 2d order, or 60, be divided by 3, the quotient will be 2 tens, or 2 units of the 2d order. If 9 hundreds, or 9 units of the 3d order be divided by 3, the quotient will be 3 hundreds, or 3 units of the 3d order. So, in general,

If units of any order be divided by simple units, the units of the quotient will be of the same order as those of the

dividend.

Let us suppose, as an example, that it were required to divide 11772 by 327.

OPERATION.

327)11772(36

981

1962

1962

To this number

We first consider, as we have a right to do, that 11772 is made up of 1177 tens and 2 units. We then divide the tens by the divisor 327, and find 3 tens for the quotient, by which we multiply the divisor and subtract the product from 1177, leaving a remainder of 196 tens. we bring down the 2 units, making 1962 units. This number contains the divisor 6 times: that is, 6 unit's times. When the unit of the first number which contains the divisor is of the 3d order, or 100, there will be 3 figures in the quotient; when it is of the 4th order there will be 4, &c.

Hence, the quotient found according to the rule, expresses the number of times which the dividend contains the divisor, and consequently is the true quotient.

Q. When the divisor is contained in simple units, what units will the quotient figure express? When the divisor is contained in tens, what units will the quotient figure express? When it is contained in hundreds? In thousands?

PROOF OF DIVISION

§ 34. Multiply the divisor by the quotient and add in the remainder, when there is one: the sum should be equal to the dividend.

EXAMPLES.

1. Divide 67289 by 261.

In this example, we find a quotient of 257 and a remainder of 212, which being less than the divisor will not con

tain it.

OPERATION.

261)67289(257

522

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67289 the dividend: Hence, the work is right

2. Divide 119836687 by 39407.

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§ 35. When two numbers are multiplied together the multiplicand and multiplier are both factors of the product; and if the product be divided by one of the factors, the quotient will be the other factor. Hence, if the product of two numbers be divided by the multiplicand, the quotient will be the multiplier; or, if it be divided by the multiplier, the quotient will be the multiplicand.

Q. If two numbers are multiplied together, what are the factors of the product? If the product be divided by one of the factors, what will the quotient be? How do you prove multiplication?

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2. The multiplicand is 61835720, the product 8162315040: what is the multiplier?

Ans. 132.

3. The multiplier is 270000, the product 1315170000000: what is the multiplicand?

Ans.

4. The product is 68959488, the multiplier 96: what is the multiplicand?

Ans. 718328.

5. The multiplier is 1440, the product 10264849920 : what is the multiplicand?

Ans.

6. The product is 6242102428164, the multiplicand 6795634: what is the multiplier?

Ans.

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-33788 rem. Ans.—-121 rem. Ans.--346 rem.

15. Divide 119184669 by 38473. Ans. 16. Divide 280208122081 by 912314. 17. Divide 293839455936 by 8405. 18. Divide 4637064283 by 57606. Ans.--11707 rom

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