Page 49 - ICSE Math 7

Example 13: Simplify: 32.105 + 9.28 – 0.0071 × 100

Solution: 32.105 + 9.28 – 0.0071 × 100
= 32.105 + 9.28 – 0.71 (Perform multiplication first according to BODMAS)
= 40.675

Example 14: Simplify: 330.9 + 2.51 – 1106.80 ÷ 100
Solution: 330.9 + 2.51 – 1106.80 ÷ 100
= 330.9 + 2.51 – 11.068 (Perform division first according to BODMAS)

= 322.342

EXERCISE 3.1

1. Convert the following decimal fractions into decimals.
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(a) 91 (b) 3 (c) 21 (d) 375 (e) 14 (f) 29 37
100 100 1,000 1,000 10 100
2. Convert the following fractions into decimals.

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(a) 4 (b) 11 (c) 37 (d) 41 121 (e) 7 (f) 19 3
125 20 500 200 50 4
3. Convert the following decimals into fractions.
(a) 2.75 (b) 0.014 (c) 6.125 (d) 0.005 (e) 0.146 (f) 3.270
4. Add the following.

(a) 460.54, 275.25 (b) 0.0275, 0.0051 (c) 4.31, 2.854
(d) 1.23, 23.101, 0.87 (e) 11.23, 16.981, 2.098 (f) 1.234, 4.567, 0.005
5. Subtract the following.

(a) 52.50 from 60.25 (b) 106.35 from 107.75 (c) 2.22 from 3.175
(d) 145.567 from 149.999 (e) 5.675 from 107.17 (f) 168.7 from 179.81
6. Find the following products.

(a) 2.51 × 10 (b) 0.0052 × 1,000 (c) 0.75 × 0.023
(d) 12.91 × 0.064 (e) 12 × 0.135 × 2.2 (f) 5.24 × 4.22 × 8.3
7. Find the quotient of the following.

(a) 0.125 ÷ 5 (b) 15.6 ÷ 12 (c) 3.42 ÷ 0.19
(d) 1.824 ÷ 1.2 (e) 295.6 ÷ 100 (f) 0.56 ÷ 1,000
8. Simplify.

(a) 9.28 + 11.65 – 15.756 (b) 11.234 + 16.98 + 2.55 (c) 20.35 – 8.57 – 9.99
(d) 10 × 205.6 + 250.65 – 104.2 (e) 150.63 ÷ 0.3 + 12.54 – 6.66

Terminating and Non-Terminating Decimals

While converting fraction into decimal, if the dividend is completely divisible by the divisor, i.e.,
there is no remainder, then the decimal is known as terminating decimal. For example, 22 = 4.4 is a

terminating decimal. 5

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