1. Rules for Significant Digits
Significant or not significant?
Digits 1-9
Significant
Zeros between two significant digits
Zeros to the right of the decimal place and right of the significant digit
Zeros used to the right of the decimal place and the left of the significant digit (placeholders)
NOT
Zeros used to the right of the significant digit but left of the decimal point are not significant

2. Example of the rules of sig figs
EXAMPLES
# OF SIG. DIG.
COMMENT
4534 kg 4
All non-zero digits are always significant.
2007 L
Zeros between 2 sig. dig. are significant.
5.00 3
Additional zeros to the right of decimal and a sig. dig. are significant.
0.007 1
Placeholders are not sig.
700(.)
Left of sig fig but right of decimal point

3. Multiplication and Division
RULE: When multiplying or dividing, your answer may only show as many significant digits as the multiplied or divided measurement showing the least number of significant digits.
22.37 cm x 3.10 cm x cm = cm3
= 5.95 x 103 cm3
(or 5950 cm3)

4. 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.
3.76 g g g = g
= 2.7 g

5. Finally…combining all together
Use PEMDAS rules, and break down sig figs one equation at a time Ex
( ) * (4.58 / 6.214)
= (7.32) * ( )
= (7.3) * (0.737)
5.38  5.4