How many significant figures are in 0.00081?
When finding significant figures, remember the following rules:
1. All non zeroes are significant.
2. All zeroes between non zeroes are significant.
3. All zeroes right of non zeroes in the decimal places are significant.
4. All zeroes left of non zeroes in the decimal places are not significant.
5. Zeroes right of non zeroes that are not in the decimal places are indeterminate.
Using rules 1 and 4 shows that the 8 and the 1 are significant, but none of the zeroes are. There are two significant figures.