N4081 Division

7. Division. The process of division is performed by using the C and D scales.

To divide 8 by 4 (see Fig. 8),
                              push hairline to 8 on D,
                              draw 4 of C under the hairline,
                              opposite index of C read 2 on D.

FIG. 8.
An alternative way to divide 8 by 4 would be,
                              to push the hairline to 8 on D,
                              draw the index of C to the 4 on D,
                              under the hairline, read 2 on D.

This procedure is similar to the procedure used in multiplication. In essence, it asks the question, "What number, when multiplied by 4, is 8?"

To divide 876 by 20.4,
                              push hairline to 876 on D,
                              draw 204 of C under the hairline,
                              opposite index of C read 429 on D.

The rough calculation 800 ÷ 20 = 40 shows that the decimal point must be placed after the 2. Hence the answer is 42.9.

These examples illustrate the use of the following rule.

Rule. To find the quotient of two numbers, disregard the decimal points, opposite the numerator on the D scale set the denominator on the C scale, opposite the index of the C scale read the quotient on the D scale. The position of the decimal point is determined from information gained by making a rough calculation.

EXERCISES Perform the indicated operations.