Page 53 - ICSE Math 7

MENTAL MATHS

1. Choose the correct answer.

(a) What is the value of 0.03784 × 1,000?
(i) 3.784 (ii) 37.84 (iii) 378.4 (iv) 3,784
(b) What is the place value of the underlined digit in 78.0123 ?

1 1 3 3
(i) (ii) (iii) (iv)
10000 1000 1000 10000
(c) The decimal number 0.72 when represented as a fraction in its lowest term is ____________.
72 36 100 18
(i) (ii) (iii) (iv)
100 50 72 25
(d) On subtracting 4.81 from 43.17, we get ____________.

(i) 38.36 (ii) 38.81 (iii) 38.17 (iv) 47.98
(e) The number seventeen and seven thousandths in decimal form is ____________.
(i) 17.7000 (ii) 17.07 (iii) 17.007 (iv) 1,77,000.00

(f) If on multiplying a decimal number by some power of 10, the place value of a digit changes
from tenths to tens, then the power of 10 is ____________.

(i) 0 (ii) 1 (iii) 2 (iv) 3
2. Write True or False.
5
(a) is a decimal fraction.
9

(b) 2.4 = 0.4 is a non-terminating decimal.
6 . .
(c) The recurring decimal 3.345 can also be written as 3.345.

(d) Both 2.25 and 2.27 when rounded off to the nearest tenth give 2.3.
(e) Zero is never a significant digit.
3. Fill in the blanks.

(a) 3.650 has ____________ significant figures.

(b) 2 can be represented as a recurring decimal by ____________ or ____________.
3
(c) The product of 0.536 and 0.071 will have ____________ decimal places.
(d) 36.452 when rounded to the nearest hundredth is ____________.

(e) The number of digits in the decimal part of 5.68 × 3.222 is ____________.

PRACTICE TIME

1. Simplify.
(a) 27.869 – 23.42 + 3.565 (b) 39.534 – 13.53 – 12.356
(c) 37 + 46.501 – 51.756 (d) 14.501 + 0.352 × 100
(e) 27.5 ÷ 25 + 25.25 – 10.10

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