1. Significant Figures

2. Rule 1: Nonzero numbers are always significant. Ex.) 72.3 has 3 sig figs.

3. Rule 2: All final zeroes to the right of the decimal are significant. Ex.) 72.30 has 4 sig figs.

4. Rule 3: Any zero between significant figures is significant. Ex.) 702.3 has 4 sig figs.

5. Rule 4: Placeholder zeroes are not significant. To remove place holder zeroes, rewrite the number in scientific notation. Ex.) 0.0034984 has 5 sig figs. Ex.) 4390 has 3 sig figs.

6. How many sig figs here? 1.2 2100 56.76 4.00 0.0792 7,083,000,000 2 2 4 3 3 4

7. How many sig figs here? 3401 2100 2100.0 5.00 0.00412 8,000,050,000 4 2 5 3 3 6

8. What about calculations with sig figs? Rule: When adding or subtracting numbers, your answer can have no more places after the decimal than the LEAST of the measured numbers.

9. Add/Subtract examples 2.45cm + 1.2cm = 3.65cm, Round off to = 3.7cm 7.432cm + 2cm = 9.432 Round off to = 9 cm

10. Multiplication and Division Rule: When multiplying or dividing, the result can have no more significant figures than the least reliable measurement.

11. A couple of examples 56.78 cm x 2.45cm = 139.111 cm 2 Round to  139cm 2 75.8cm x 9.6cm = ?