Correct any answers that have the incorrect number of significant figures.

(a) 34.00 ×567 ÷ 4.564 = 4.2239 ×103

(b) 79.3 ÷ 0.004 ×35.4 = 7 ×105

(c) 89.763 ÷ 22.4581 = 3.997

(d) (4.32 × 1012) ÷ (3.1 × 10−4) = 1.4 × 1016

Solution 59P

Step 1:

(a) 34.00 ×567 ÷ 4.564 = 4.2239 ×103

34.00 ×567 =19278

Here the least number of significant figures is two , hence the above answer is rounded off as 19.

Now, 19÷ 4.564 =4.16301

Here the least number of significant digits are two , hence the above answer is rounded off as 4.2104

Thus the given answer 4.2239 ×103 is incorrect.

Step 2:

(b) 79.3 ÷ 0.004 ×35.4 = 7 ×105

79.3 ÷ 0.004 =3.5310(actual answer by using calculator )

Answer after rounding off is 3

Now, 335.4 = 106.2(actual answer by using calculator )

Answer after rounding off is 1×103

Thus the given answer 7 ×105 is incorrect.