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Multiplying and Dividing
 

 RULE: When multiplying or dividing, your answer may only show as many significant digits as the least number of significant digits in the measurements you are working with.

 Example: When multiplying 22.37 cm x 3.10 cm x 85.75 cm = 5947.76 cm³
                but must be rounded to 5950 cm³.

 We look to the original problem and check the number of significant digits in each of the original measurements:

                                         22.37 shows 4 significant digits.

                                         3.10 shows 3 significant digits.

                                         85.75 shows 4 significant digits.

Our answer can only show 3 significant digits because that is the least number of significant digits in the original problem.

5946.76 shows 6 significant digits, we must round to the tens place in order to show only 3 significant digits. Our final answer becomes 5950 cm3.
 

Adding and Subtracting
 

RULE: When adding or subtracting your answer can only show as many decimal places as the measurement having the fewest number of decimal places.
 

Example: When we add 3.76 g + 14.83 g + 2.1 g = 20.69 g
 

We look to the original problem to see the number of decimal places shown in each of the original measurements. 2.1 shows the least number of decimal places. We must round our answer, 20.69, to one decimal place (the tenth place). Our final answer is 20.7 g