﻿ Significant Figures Rules | Examples | Sig Figs less than 1 explained | Math Warehouse

# Significant figures

#### What are significant figures? They are the digits that 'count' or 'matter'
Consider for example if a microscope can measure with an accuracy of a hundredth and it measures that small object is 0.25 units. Well, that means that if we use this microscope's measurements in some other calculations then we never really can be more accurate than the hundredth place.

Examples
 314 3 significant digits 310 3 significant digits 0314 3 signficant digits 304 3 significant digits 001 1 significant digit 200 2 significant digits 200 2 significant digits
Some Takeaways from the examples above:
• leading zeros do not count (see examples 3 and 5)
• If you have several trailing zeros like examples 6 and 7, then you can underline the last significant digit (example 7) OR you can overline it like example 6.

#### Significant Digits Less than 1, like .0015

You do not count the leading zero's.
So, there are 2 significant digits in .0015

### Practice Problems

Number How many significant figures?
Two
Two

4
We are using the overline notation to indicate that the final zero is indeed a significant digit.

4
Writing out the '.0' as a decimal point (instead of writing '300') implies that all digits are significant.
Therefore, all 4 digits are significant

2
Underlining the '0' is 1 of the ways to indicate that that digit is the last (or 'least' ) significant digit
Therefore, only 2 digits are significant.

1
You can only assume that the first digit. the '3' is significant.

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