Imagine you have to take a measurement using the ruler shown below:
Inches are marked in red. Centimeters are marked in blue. Millimeters are marked in green.
Here, our smallest unit of measurement is the millimeter. 1 Millimeter is our "Precision Unit"
When used correctly, the greatest possible error for this instument is half of its precision unit, or 1/2 of a Millimeter.
Here, we've taken a measurement of 14.6cm. This measurement has three significant digits.
How do we count significant digits?
|Counting Significant Digits|
1. All nonzero digits are significant.
2. Zeros between significant digits are also significant.
3. Zeros used to show place values are not significant.
4. In numbers with a decimal point, all zeros to the right of a nonzero digit are significant.
Below, we count the number of significant digits in four numbers: