S. K. Gupta Anubhuti Gangal Class 5 Math Eighth Chapter Decimals Exercise 31
EXERCISE 31
Multiply:
(1) 1.13 × 0.7
= 0.791
(2) 21.05 × 0.8
= 16.84
(3) 19.2 × 0.003
= 0.0576
(4) 0.004 × 1.3
= 0.0052
(5) 83.7 × 5.9
= 493.83
(6) 89.65 × 6.8
= 609.62
(7) 1.57 × 0.018
= 0.02826
(8) 1.035 × 16.3
= 16.8705
(9) 23.02 × 49.3
= 1134.886
(10) 25.3 × 16.7
= 422.51
(11) 0.3 × 0.4 × 0.02
= 0.3 × 0.008
= 0.0024
(12) 0.02 × 0.03 × 0.0001
= 0.02 × 0.00003
= 0.00000006
(13) 0.1 × 0.02 × 0.003 × 0.004
= 0.1 × 0.02 × 0.000012
= 0.1 × 0.0000024
= 0.000000024
(14) 39.8 × 400
= 15920
(15) 65.12 × 7000
= 455840
(16) If 59 × 8.7 = 513.3, find the product in each of the following without multiplication.
(a) 5.9 × 8.7
= 51.33
(b) 5.9 × 87
= 513.3
(c) 0.59 × 87
= 51.33
(d) 0.59 × 8.7
= 5.133
(e) 0.59 × 0.87
= 0.5133
(f) 5.9 × 0.87
= 5.133
(g) 0.059 × 0.0087
= 0.0005133
(17) Alok weighs 50.87kg. His father is 1.5 times heavier than he is. Calculate his father’s weight.
Solution: the required weight of Alok’s father (in kg) = (50.87 × 1.5) =76.305 kg.
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