1. How many significant figures? 0.002 0.0030 1.0020 45.0 2.010
Bellringer 9/11/09
How many significant figures?
0.002
0.0030
1.0020
45.0
2.010

2. Today’s Objective
Students will be able to work with significant figures

3. Rules for Calculating with Sig Figs
Addition or Subtraction
Rule: The final answer should have the same number of digits to the right of the decimal as the measurement with the smallest number of digits to the right of the decimal.

4. Example
= which rounds off to 103.2

5. Rules Continued
Multiplication or division
The final answer has the same number of significant figures as the measurement having the smallest number of significant figures

6. Example
123 x 5.35 = which rounds off to 658

7. Rules for rounding Round down when:
The digit following the last sig fig is a 0,1,2,3, or 4
The last sig fig is even and the next digit is 5

8. Rules for rounding Round up when:
The digit following the last sig fig is a 6,7,8, or 9
The last sig fig is odd and the next digit is 5