Question

1. Consider the following numbers
A = 3.205 x 103 B= 2.993645 x 102 C = 1.6 x 10-22 D = 22 Find (i) A+B+D (ii) D-C (iii) AxD (iv)​

Answer 1

Consider the following numbers

A = 3.205 × 10³ , B = 2.993645 × 10²

C = 1.6 × 10¯²² , D = 22

To find : (i) A + B + D (ii) D - C (iii) A × D

solution : here we have to use concept of significant figure of addition, subtraction and multiplication.

in addition/subtraction : we should round the sum and difference to the same number of decimal places as the measurement with the fewest decimal places.

(i) A + B + D = 3.205 × 10³ + 2.993645 × 20² + 22

= 3205 + 299.3645 + 22

= 3,526.3645 = 3526

(ii) D - C = 22 - 1.6 × 10¯²² ≈ 22

in multiplication : we should round the product so that it has the same number of significant figures as the least-precise measurement.

(iii) A × D = 3205 × 22 ( least significant fig = 2)

= 70510

so, 7100 (significant fig = 2) is the answer after rounding the product.