Problem 10: Calculate the answer up to appropriate numbers of significant figures.

(a) 168.99 × 9 (b)23.5 + 234.09 (c) 984.25/80.0

Solution

(a)

Now the least number of significant figures in the question is in 9 (1 sig fig), therefore, the final result would be rounded off to one significant figure.

(Note: There is one sig fig in the above answer).

(b)

23.5 + 234.09 = 257.59

In the case of addition, the answer is determined by the most uncertainty. 23.5 has more uncertainty than 234.09, therefore, the answer is rounded off to one decimal place.

(c)

The least precise number is 80 (has 2 sig figs). The result should be rounded off to 2 sig figs.