1. Significant Figures

2. Rule 1: All non-zero digits are significant. Ex: 48.7 2962
= 3 SF
= 4 SF

3. Rule 2: Zeros in the middle of a series of numbers are significant
Rule 2: Zeros in the middle of a series of numbers are significant. Ex: ,702 50,008
= 3 SF
= 6 SF
= 5 SF

4. Zeros in front of a series of numbers are not significant.
Rule 3:
Zeros in front of a series of numbers are not significant.
(They are being used as place holders to insure the correct number of decimal places.)
Ex:
0.473
0.0305
= 1 SF
= 3 SF
= 3 SF

5. Rule 4: Zeros to the right of a decimal are significant. Ex: 3. 00 437
= 3 SF
= 6 SF
= 5 SF

6. Rule 5: Zeros at the end of a number that are followed by a decimal are significant. Ex: 2000.
= 4 SF

7. Rule 6:
Zeros at the end of a number that does not have a decimal are not considered to be significant.
(They may be significant, but we do not have enough information to be sure.)
Ex: 2000
assume 1 SF

8. Atlantic – Pacific Rule
Pacific Rule - If a decimal is PRESENT start counting with the first non-zero digit from the left.
Pacific Side:
decimal present
0.0019
65.01
0.0300
700.
Atlantic Side:
decimal absent
80200
400000
32105
700
2 SF
3 SF
4 SF
1 SF
3 SF
5 SF
3 SF
1 SF
Atlantic Rule – If the decimal is ABSENT start counting with the first non-zero digit from the right.

9. Rules for doing calculations
The answer to a set of calculations can not be more accurate than the least accurate value used in the calculation.

10. Multiplication and Division
The number of significant figures in the answer is equal to the lowest number of significant figures used in the calculation.
Ex 1: x =
this will be reported with 3 SF as 175
Ex 2: /4.2 =
this will be reported with 2 SF as 2.0

11. Addition and Subtraction
Use the same number of decimal places as the least accurate value.
(smallest number of decimal places)
Ex 1: =
This will be reported as 57.1
Ex 2: 240 – 71.3 = 168.7
Round to the tens place and report as 170