Significant Figures

- are digits used to establish the value of a certain number or measurement.

A Rules of Determining the Number of Significant Figures:

1. All nonzero digits are "always significant".
2. Leading zeros are "never significant". (leading zeros are zeros before nonzero digits)
3. Captive zeros are "always significant". (captive zeros are zeros between nonzero digits)
4.  Trailing zeros are may or may not be significant. Trail zeros are "significant only" if the number has decimal point.