Chemistry Significant Figures with addition and subtraction.

Question

Express the answers to the following operations with the proper number of significant figures.

 

(a) 87.5 + 1.3362

 

(b) 429 − 410.5

 

(c) 1.2364 − 1.07

 

(d) 1.5152 + 0.17 + 0.0003

 

Answer 1

When performing addition and/or subtraction, the number of significant figures (sig figs) in the answer should be based on the number of decimal places so the answer should not contain more sig figs to the right of the decimal than the fewest of any of the values used in the calculation.

(a) 87.5 + 1.3362 = 88.8362 = 88.8 (1 decimal place)

 

(b) 429 − 410.5 = 18.5 = 19 (no decimal places)

 

(c) 1.2364 − 1.07 = 0.1664 = 0.17 (2 decimal places)

 

(d) 1.5152 + 0.17 + 0.0003 = 1.6855 = 1.69 (2 decimal places)