There are three rules on determining how many significant figures are in a number:

**Non**-zero digits are always significant. Any zeros between two significant digits are significant. A final zero or trailing zeros in the decimal portion ONLY are significant.Also, how do you determine the number of significant figures?

**Rules for Numbers WITHOUT a Decimal Point**

- START counting for sig. figs. On the FIRST non-zero digit.
- STOP counting for sig. figs. On the LAST non-zero digit.
- Non-zero digits are ALWAYS significant.
- Zeroes in between two non-zero digits are significant. All other zeroes are insignificant.

How many significant figures does 100.0 have?

3. Trailing zeros in a number are significant only if the number contains a.

decimal point.

Example: 100.0 has

decimal point.

Example: 100.0 has

**4 significant figures**.What is the significant numbers?

The

**significant**figures (also known as the**significant**digits) of a**number**are digits that carry meaning contributing to its measurement resolution. Trailing zeros when they are merely placeholders to indicate the scale of the**number**(exact rules are explained at identifying**significant**figures); and.