Perform the indicated operation and give an answer with the proper number of significant figures: 48.2 m + 3.87 m + 48.4394 m

Answer 1

When performing addition, the number of significant figures in the answer is determined by the number of decimal places. In this particular problem, we have 48.2 m + 3.87 m + 48.4394 m = 100.5094 but since the number 48.2 has only one decimal place, this dictates the number of decimal places in the answer, and by extension, the number of significant figures in the answer. So, we round the answer to 100.5 and yes, it does have 4 significant figures, but only one decimal place.

Answer 2

Hi, Elle,

This seems to be a straightforward addition, with special attention given to significant figures.

The sum of the numbers as written is 100.5094 m. But two of the numbers have only 3 significant digits (3.87 and 48.2). That limits the answer to 3 sig figs, so it should be written as 101 (some might say 100, since it is an even number, but it is closer to 101).

Bob