1. Significant Figures
Significant figures – the digits in any given number that give us useful information about that number
Imagine a map of the U.S.
Use the Atlantic Pacific Rule:
If the decimal is absent count from the Atlantic side.
If the decimal point is present, count from the Pacific side.
In both cases, start counting with the first non-zero digit.

3. Significant Figures The Atlantic Pacific Rule
Atlantic – "A" is for decimal point is absent.
If there is no decimal point, start counting significant digits with the first non-zero digit on the right.
Examples:
(a) 140,000
(b) 20060

4. Significant Figures The Atlantic Pacific Rule
Pacific – "P" is for decimal point is present.
If a decimal point is present, count significant digits starting with the first non-zero digit on the left.
Examples:
(a)
(b) 18.00

5. Significant Figures Examples: 96,002 g 0.044 g 200. g 4.7200 km 82.0 mkg
5 sig figs
2 sig figs
3 sig figs
5 sig figs
3 sig figs
4 sig figs
3 sig figs
1 sig figs
3 sig figs

6. Significant Figures: Multiplying/Dividing
What is 2.02 x x 0.003? a b c d e

7. Significant Figures: Multiplying/Dividing
Rule
Find the number with the least amount of significant figures
Report your answer with that many significant figures.

8. Significant Figures: Multiplying/Dividing
What is 2.02 x x 0.003? a b c d e

9. Significant Figures: Adding/Subtracting
Rule:
Find the number with the least amount of decimal places.
Report your answer with that many decimal places.

10. Significant Figures: Adding/Subtracting
What is ? a b c
d. 21.6
e. 21

11. Scientific Notation
Scientific notation – usually used to express very large or very small numbers
Steps for converting to scientific notation:
1. Move decimal place until only one number is to the left of the decimal
2. Count how many places you moved and use this number as your exponent
3. If the number you started with is larger than one, the exponent is positive. (smaller than one, exponent is negative)
Example: in scientific notation = 7.2 x 103

12. Scientific Notation Convert the following to scientific notation:
a. 30,100,000 b
c d
Answers:
a x 107 b x 10-5
c x 102 d x 10-3
Show examples A and B on the board. Show how to move the decimal and count
Have students work C and D independently.

13. Scientific Notation Expand the following: Answers a. 0.0503 b. 160,000
a x b x 105
c x d x 103
Answers
a b. 160,000
c d. 9980

14. Extra Practice
This website has extra practice if you are having trouble with significant figures. If you answer a question incorrectly, it tells you why you were not correct.
Don’t forget to use the Atlantic-Pacific Rule!