1. Significant Digits Uncertainty of Measurement

2. Three Rules Non-zero digits are significant Zeros between two significant digits are significant Zeros at the right end of a number, after a decimal point, are significant

3. Non-zero digits are significant Number 455.6 7.98 0.6224 5.2 Significant Digits 4 3 4 2

4. Zero to left of decimal point 0.788955 significant digits The zero to the left of the decimal point is there to communicate that the decimal point is a decimal point - convention

5. Problems! Numbers like 308.5 0.000811 5000

6. Zeros between non-zero digits are significant Number 28.09 1008.91 3.005 2.03 Significant Digits 4 6 4 3

7. Space Holding zeros on numbers less than one 0.006783 significant digits 0.0300865 significant digits

8. Trailing Zeros 200 is considered to have only one significant digit 38,000 has two significant digits

9. Problem area 5000 might really have four significant digits - an exact count or measurement write number as 5000. Scientific notation used to indicate significant digits

10. Review 78002.1 0.00006003 34.61 8.81 42,300 6 4 3

11. Multiplication & Division An answer cannot have more significant digits than the measurement with the least number of significant digits used in the operation. (3.006) X (0.0067) = 0.0201402 = 0.020 only 2 sig. Digits

12. Addition & Subtraction The answer is rounded to the least number of places in the decimal portion of any number in the operation 134.008 89.70 57.9 281.608 = 281.6