# How do you reduce a number to a certain number of significant digits?

May 20, 2017

Follow a step by step process.

#### Explanation:

Step 1. Underline the number of significant figures you need
Example. If you need to reduce $5572$ to 2 significant figures, underline the two numbers on the left: $\underline{5} \underline{5} 72$

Step 2. Look at the next number (not underlined)
Example. $\underline{5} \underline{5} \textcolor{red}{7} 2$

Step 3. Round up or down depending on the following rule
- If the next number is 5 or more, round up
- If the next number is 4 or less, round down
- Change the remaining numbers to zero
Example. $\underline{5} \underline{6} 0 0$