1. 5. Significant Figures-
= represent the valid digits of a measurement and tells us how good your instrument is.

2. A. Rules for Significant Figures:
Rule #1: Numbers other than zero are always significant.
96 g
2 sig figs
61.4g
3 sig figs
0.52 g
2 sig figs

3. Rule #2: One or more final zeros used after
the decimal point are always significant.
4.72 Km
3 sig figs Km
5 sig figs
82.0 Km
3 sig figs

4. Rule #3: Zeros between two other significant
digits are always significant.
5.029 m
4 sig figs
306 m
3 sig figs

5. Rule #4: The rest of the zeros are not significant.
1 sig figs
3 sig figs

6. MORE PRACTICE Identify the number of sig figs 345 ml 0.1120 g 3000 kg
0.01 cm
340 ml

7. ***When adding or subtracting give the answer in the least number of decimal places!!

8. EXAMPLE:
= 50.1
23,345 m m = m
15.0 ml – 5 ml = 10 ml

9. ***When multiplying or dividing give the answer in the least number of significant figures!!

10. 50.0 m x .09 m = 5 m2