Sig Fig Calculations
For calculations, remember that an answer cannot be more precise than the least precise
number used to get the answer.
For addition and subtraction, the result is rounded off so that it has the same number of
decimal places as the measurement having the fewest decimal places.
Ex.
97
+ 6.783 = 104
2 SF
4 SF
3 SF
When multiplying or dividing, the number of significant figures in the answer is equal to
number of significant figures in the least precise measurement.
Ex.
3.0 × 0.0492 = 0.15
2 SF
3 SF
2 SF
Problems:
1) 16.5 mL + 8 mL + 4.37 mL
2) 13.25 cm3 + 10.00 cm3 + 9.6 cm3
3) 23.27 g – 12.058 g
4) 350.0 L – 200 L
5) 2.6 m × 3.78 m
6) 0.036 g × 0.02 g
7) 35 cm ÷ 0.62 cm
8) 0.075 mL ÷ 3 mL