What is the rules in the determining significant figure?

Answer 1

Multiplication and Division

Round the answer to the same number of significant figures (sig figs) as the measurement with the fewest sig figs in the problem.

34.9cm x 4.7cm = 164.03cm2 = 160cm2 (rounded to two sig figs)

271.0g/99.8cm3 = 2.71543g/cm3 = 2.715 (rounded to four sig figs)

Addition and Subtraction

Round the answer to the same number of decimal places as the measurement with the fewest decimal places.

9.45kg + 8.329kg = 17.78kg (rounded to two decimal places)

120.2589m - 12.351m = 107.908m

Rounding Rules:

If the number to be dropped is less than four, keep the number in front the same. For example, 3.43 would be rounded to 3.4 .

If the number to be dropped is greater than five, round the number in front up by 1. For example, 3.46 would be rounded to 3.5 .

If the number to be dropped is exactly five, keep the number in front the same if it is even. If the number in front is odd, round up by 1.

4.65 rounds to 4.6 .

4.75 rounds to 4.8 .