Significant figures

Question

Carry out each calculation and report the answer using the proper number of significant figures .

a. 65.4 * 0.21

b. 92.0/18

c. 840.8 * 0.4

Answer 1

Good afternoon, Josephine.

When multiplying or dividing, the rule is that your answer is limited by the number in the problem that has the least amount of sig figs.

In problem a, 65.4 has three sig figs. 0.21 has two sig figs, as the leading zero is not considered significant. Therefore, the answer is limited to two sig figs. 65.4 X 0.21 = 14

Problem b: 92.0 / 18 = 5.1 (the answer is limited to two sig figs because 18 has two sig figs)

Problem c: In this problem, 0.4 has only one significant figure, as the leading zero is not significant. Therefore, the answer is limited to one sig fig.

840.8 X 0.4 = 300

(Trailing zeroes are not counted as significant when there is no decimal in the number. Therefore, the number 300 has only one significant figure.)