Page 57 - Start Up Mathematics_7

Step 2: When the division of whole number part of the dividend is complete, put the decimal
point in the quotient and proceed further with the division the way we perform in whole
numbers.

Example 19: Divide: (a) 19.81 by 7 (b) 0.364 by 7

Solution: (a) 7 19.81 2.83 Alternative method:
1
– 14 19.81 ÷ 7 = 1981 × = 1981 × 1
58 100 1 7 7 100
– 56 = 283 × 100 = 2.83
21
– 21 ∴ 19.81 ÷ 7 = 2.83

0

(b) 7 0.364 0.052 Alternative method:
– 0 364 1 364 1
3 0.364 ÷ 7 = 1,000 × = 7 × 1,000
7
–0 1
36 = 52 × 1,000 = 0.052
–35 ∴ 0.364 ÷ 7 = 0.052

14
–14
0

Example 20: Evaluate: (a) 0.6 ÷ 2 (b) 851.2 ÷ 4
6 6 1 6 1 3
Solution: (a) 0.6 ÷ 2 = ÷ 2 = × = × = = 0.3
10 10 2 2 10 10
8,512 8,512 1 8,512 1 2,128
(b) 851.2 ÷ 4 = ÷ 4 = × = × = = 212.8
10 10 4 10 10 10

Division of a Decimal Number by Another Decimal Number

In order to divide a decimal number by another, follow these steps:

Step 1: Convert the divisor into a whole number by multiplying the divisor and dividend by 10,
100 or 1,000, etc.

Step 2: Now proceed as we divide a decimal number by a non-zero whole number.
Example 21: Divide:

(a) 0.5 by 0.25 (b) 19.1484 by 3.24

Solution: (a) 0.5 ÷ 0.25
Converting divisor to a whole Alternative method:
number, we get 5 25 5 100 10
10
5
10
0.5 0.5 × 100 50 0.5 ÷ 0.25 = ÷ 100 = × 25 = = 2
0.25 = 0.25 × 100 = 25 = 2
49