Page 52 - ICSE Math 7

EXERCISE 3.2

1. Find whether the following are terminating or non-terminating decimals.

(a) 3 (b) 3.36 (c) 42 (d) 7 (e) 3.25 (f) 4
8 6 9 12 1.3 11

2. Express the following fractions as recurring decimals.

(a) 15 (b) 7 (c) 3 (d) 4 (e) 5 (f) 10
22 15 11 9 18 18

3. Convert the following recurring decimals into fractions.
. . .
(a) 0.5 (b) 2.324 (c) 0.81 (d) 1.126 (e) 0.91
4. Round off the following to the nearest hundredth.

(a) 3.0901 (b) 0.0567 (c) 21.3438 (d) 0.099
5. Round off the following correct to three decimal places.

(a) 0.0567 (b) 8.1002 (c) 0.0598 (d) 31.2455
6. Round off the following numbers as indicated.
(a) 0.6089 correct to two significant figures.

(b) 0.0071 correct to three significant figures.

(c) 19.009 correct to three significant figures.
(d) 7.0903 correct to four significant figures.
(e) 10.8 correct to five significant figures.

AT A GLANCE
¾ A decimal number has two parts: the integral part and the decimal part.

¾ Decimal places in a decimal number are the number of digits on the right of the decimal point.
¾ Fractions having denominator 10 or higher powers of 10 are known as decimal fractions.

¾ Like decimals are the decimals having same number of decimal places.
¾ Unlike decimals are the decimals having different number of decimal places.

¾ While performing fundamental operations on decimals, we convert the decimals into like decimals
first.

¾ Simplification of decimals is carried out by using the rules of BODMAS.

¾ If the dividend is completely divisible by the divisor, then the decimal is known as terminating
decimal otherwise it is non-terminating decimal.

¾ A decimal in which a digit or a group of digits repeat themselves is known as a recurring
decimal.
¾ The process of expressing a decimal number up to a specific number of decimal places is known
as approximating or rounding off.

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