Question

A chemist weighed three separate test samples at 0.17 gram, 0.204 gram, and 2.3 grams. What is the total weight of the three samples?

Answer 1

The word "total" tells you that we have to add:
0.17 g+ 0.204 g+ 2.3 g= 2.674 g.

Since 2.3 (g) has the least significant figures (which is 2) among the three numbers, the answer should also have 2 significant figures.

The final answer is 2.7 g.

Hope this helps~