1. Significant Figures
Revisiting the Rules

2. Rules for Determining Number of Significant Figures
All nonzero digits are significant.
e.g
Zeros in the middle are significant.

3. Rules for Determining Number of Significant Figures
Zeros at the beginning are NOT significant.
e.g
Zeros at the end are significant if there is a decimal point! NO DECIMAL, NOT SIGNIFICANT.
e.g. 63, ,000

4. Rules for Determining Number of Significant Figures
In multiplication and division, the answer cannot have more significant figures than the least of the original numbers.
e.g. 766 x 6.7 = = 510 (9 rounds up to 10)
e.g. 300 ÷ = = 3
(3.0 is not correct, adding decimal places adds significant figures)

5. Rules for Determining Number of Significant Figures
In addition and subtraction, the answer cannot have more digits after the decimal point than either of the original numbers.
e.g = = 76.1
e.g = =
In problems with mixed operations (+,- and x, ÷) use the proper rule and round appropriately before doing the other type of operation.

6. Rules for Determining Number of Significant Figures
All nonzero digits are significant.
Zeros in the middle are significant.
Zeros at the beginning are NOT significant.
Zeros at the end are significant if there is a decimal point! NO DECIMAL, NOT SIGNIFICANT.
In multiplication and division, the answer cannot have more significant figures than the least of the original numbers.
In addition and subtraction, the answer cannot have more digits after the decimal point than either of the original numbers.