1. Significant Figures Used to report all precisely known numbers + one estimated digit

2. Rule #1 Every nonzero digit is significant Every nonzero digit is significantExamples: 24 = 2 3.56 = 3 7 = 1

3. Rule #2 Zeros between non-zeros are significant Zeros between non-zeros are significantExamples: 7003 = 4 40.9 = 3

4. Rule #3 Zeros appearing in front of non-zero digits are not significant Zeros appearing in front of non-zero digits are not significant Act as placeholders Act as placeholders Can’t be dropped, show magnitude Can’t be dropped, show magnitude Examples: Examples: 0.00024 = 2 0.453 = 3

5. Rule #4 Zeros at the end of a number and to the right of a decimal point are significant. Zeros at the end of a number and to the right of a decimal point are significant.Examples: 43.00 = 4 1.010 = 4 1.50 = 3

6. Rule #5 Zeros at the end of a number decimal point Zeros at the end of a number when no decimal point is present aren’t significant.Examples: 300 = 1 27,300 = 3

7. Special Rule Always remember PA Always remember PA PA If a decimal point is present, start on the Pacific (P) side and begin counting at the first non-zero digit all the way to the end. If a decimal is absent, start on the Atlantic (A) side and begin counting at the first non-zero digit all the way to the end.

8. Special Rule (cont.) Remember PA Remember PAExamples: 123.003 = decimal present, start on “P” side, begin counting Answer = 6

9. Special Rule (cont.) Remember PA Remember PAExamples: 204,000 = decimal absent, start on “A” side, begin counting at first non- zero digit until you hit the end of the number. Answer = 3

10. Sig. Fig. Math Rules Multiplication / Division: Multiplication / Division: Your answer can’t have more sig. figs. than the number in the problem with the least amt. of sig. figs. Example = 60.56227892 x 35.25 Calculator says – 2134.890832 (wrong) Answer - 2135

11. Sig. Fig. Math Rules Addition / Subtraction: Addition / Subtraction: Answers can’t have more numbers to the right of the decimal point than the number in the problem with the least amt. of numbers to the right of the decimal point. Example = 24.1 + 3.35 + 2.23 Calculator says – 29.68 (wrong) Answer – 29.7