Using Significant Figures in Calculations
Any time you perform a calculation, you need to make sure to express the result with the correct number of significant figures. There are only two rules you need to know for performing calculations with significant figures:
 When multiplying or dividing two or more factors, the result should have the same number of significant figures as the factor with the smallest number of significant figures.
 When adding or subtracting two or more terms, the result should have the same number of decimal places as the term with the smallest number of decimal places.

