# How many significant digits does 20.0020 have?

Sep 15, 2016

6

#### Explanation:

Significant figures include all digits of a measured quantity including the uncertain one.

The following are the rules on how to "count" significant figures:

1. All nonzero digits are significant.
2.Zeros at the beginning of a number are never significant.
ex. 0.02 has only 1 significant figure; 0.0026 has 2 significant figures
2. 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
3. Zeros between nonzero digits are significant.
ex. 1.03 has 3 significant figures; 20.0020 has 6 significant figures

In calculations,

1. Addition and subtraction:
The results should have the same number of decimal places as the measurement with the fewest decimal places.
2. Multiplication and division:
The results should have the same number of significant figures as the measurement with the fewest significant figures.

Hope this helps! :)