Significant figures include all digits of a measured quantity including the uncertain one.
The following are the rules on how to "count" significant figures:
- All nonzero digits are significant.
2.Zeros at the beginning of a number are never significant.
ex. 0.02 has only 1 significant figures; 0.0026 has 2 significant figures
- Zeros at the end of a number are significant if the number contains a decimal point.
ex. 0.0200 has 3 significant figures; 3.0 has 2 significant figures
- Zeros between nonzero digits are significant.
ex. 1.03 has 3 significant figures; 50007 has 5 significant figures
- Addition and subtraction:
The results should have the same number of decimal places as the measurement with the fewest decimal places.
- Multiplication and division:
The results should have the same number of significant figures as the measurement with the fewest significant figures.
Hope this helps! :)