Solve using the correct number of significant digits. 17.5 ft + 2.25 ft + 13.5 ft = ft

Question

i need help with this question because i am dooing my homework

Answer 1

When doing addition, you limit your answer based on the the number with the fewest digits after the decimal.  Thus, 17.5 + 2.25 + 13.5 = 33.25 but you can have only 1 digit following the decimal (based on 17.5 and 13.5). Thus, the answer should be 33.3 (3 significant figures).