1. Significant Figures

2. Rules: #1 – Nonzero digits are significant19
311
7862
1,237,983
#2 – Zeros between significant figures are significant
109
5002
6507
1,000,341

3. Rules #3 – Final zeros after a decimal are significant
10.0
234.00
#4 – Zeros that are placeholders are NOT significant 10
0.0003
350,000
0.099

4. Rounding When rounding to a specific amount of significant figures:
In scientific notation, all numbers preceding “x10” are significant
5-9 as next digit: round up
1-4 as next digit: round down
If you end up with zeros that need to be significant, but are not:
Add a decimal at the end of the number
All previous digits are then significant
100 rounded to 3 significant digits = 100.
Add a bar over the final significant zero
100 rounded to 2 significant digits = 100

5. The Quick Method:
If there is a decimal, count all digits to the right of the first nonzero digit as significant.
0.0005
10.010
10,120.0
If there is NOT a decimal, count all digits to the left of the first nonzero digit.
10,000
230,450
250
1,205,375,000