1. Significant Figures and Rounding
August 18, 2014

2. Sig Fig Rules Non Zero digits are significant
Zeros between two non zero digits are significant
Trailing zeros before the tenths place are not significant
Leading zeros after the decimal point are not significant
Trailing zeros after the decimal point are significant

3. Non Zero digits are significant
How many significant figures are in the following?
72.3
327
1,465 9
123,987

4. Zeros between two non zero digits are significant
How many significant figures are in the following?
101
2,302
500,078
1.009
78.02

5. Trailing zeros before the tenths place are not significant
How many significant figures are in the following?
190 80
100,000,000
4,520
67,070

6. Leading zeros after the decimal point are not significant
How many significant figures are in the following?
0.0019
0.0435

7. Trailing zeros after the decimal point are significant
How many significant figures are in the following?
1.90
23.960
456,

8. How Many Sig Figs?
3.7745
205
1.700
350.0
4,000,000,001
2.89 x 104

9. Rounding Rules Don’t do anything for 4 or less
If greater than five round up
If 5 followed by a nonzero digit round up
If 5 followed by a zero, if last sig fig is even stay, if last sig fig is odd round up

10. Greater or less than 5 Round to three sig figs 2.546  2.55
2.543  2.54

11. Rounding 5’s Round to 3 sig figs Followed by a non zero digit
 2.56
 2.56
Followed by a zero
 2.56 (if odd round up)
 2.54 (if even stay the same)

12. Round the following to 4 sig figs
84,791
256.75
4.9356
136,758
308,659,000
2.0145