Multiplying and Dividing with Significant Figures
What is the area of a rectangle with sides of length 201 m and 1.4 m?
2
3
201 m
x1.4 m
804
2010
281.4 m2
 280 m2
Keep in your answer everything you are
sure of plus one estimated digit.
Consider the number of significant figures in
the original measurements and the number of
significant figures in the answer.
The answer has only 2 significant
figures, the least number of significant
figures in the original measurements.
Multiplying and Dividing with Significant Figures
What is the area of a rectangle with sides of length 21 m and 4 m?
1
2
21 m
x4 m
84 m2
 80 m2
Keep in your answer everything you are
sure of plus one estimated digit.
In this case we are sure of nothing, therefore we can
only keep a single estimated digit in the answer.
The answer has only 1 significant figure, the least
number of significant figures in the original
measurements.
Rules for multiplying and dividing with Significant Figures
1. Multiply or divide.
2. Round the answer to the least number of
significant figures in any measurement.
Multiplying and Dividing with Significant Figures
What is 32.0 m  16 s?
s 2
3
32.0 m
16 s
1. Multiply or divide.
s
 2.0 m
2. Round the answer to the least number of
significant figures in any measurement.
s2
m
s m s
s
s
m 1
 
s s
m 2
s