Question

Find the product:

(i) 13 × 1.3 × 0.13
(ii) 2.4 × 1.5 × 2.5
(iii) 0.8 × 3.5 × 0.05
(iv) 0.2 × 0.02 × 0.002
(v) 11.1 × 1.1 × 0.11
(vi) 2.1 × 0.21 × 0.021

Answer 1

(i) First, we will find the product 13 ⨯ 1.3 ⨯ 0.13.
Now, 13 ⨯ 13 ⨯ 13 = 169 x 13
= 2197

Sum of decimal places in the given numbers = (1 + 2) = 3
So, the product must have three decimal places.

∴ 13 ⨯ 1.3 ⨯ 0.13 = 2.197

(ii) First, we will find the product 2.4 ⨯ 1.5 ⨯ 2.5.
Now, 24 ⨯ 15 ⨯ 25 = 360 x 25
= 9000

Sum of decimal places in the given numbers = (1 + 1 + 1) = 3
So, the product must have three decimal places.

∴ 2.4 ⨯ 1.5 ⨯ 2.5 = 9.000
= 9

(iii) First, we will find the product 0.8 ⨯ 3.5 ⨯ 0.05.
Now, 8 ⨯ 35 ⨯ 5 = 280 ⨯ 5
= 1400

Sum of decimal places in the given numbers = (1 + 1 + 2) = 4
So, the product must have four decimal places.

∴ 0.8 ⨯ 3.5 ⨯ 0.05 = 0.1400
= 0.14

(iv) First, we will find the product 0.2 ⨯ 0.02 ⨯ 0.002.
Now, 2 ⨯ 2 ⨯ 2 = 4 ⨯ 2
= 8
Sum of decimal places in the given numbers = (1 + 2 + 3) = 6
So, the product must have six decimal places.

∴ 0.2 ⨯ 0.02 ⨯ 0.002 = 0.000008

(v) First, we will find the product 11.1 ⨯ 1.1 ⨯ 0.11.
Now, 111 ⨯ 11 ⨯ 11 = 1221 ⨯ 11
= 13431

Sum of decimal places in the given numbers = (1 + 1 + 2) = 4
So, the product must have four decimal places.

∴ 11.1 ⨯ 1.1 ⨯ 0.11 = 1.3431

(vi) First, we will find the product 2.1 ⨯ 0.21 ⨯ 0.021.
Now, 21 ⨯ 21 ⨯ 21 = 441 ⨯ 21
= 9261

Sum of decimal places in the given numbers = ( 1 + 2 + 3) = 6
So, the product must have six decimal places.

∴ 2.1 ⨯ 0.21 ⨯ 0.021 = 0.009261