To find the *percent change* (increase or decrease), use the formula given in Example
.

##### Example 1

Last year, Harold earned $250 a month at his after‐school job. This year, his after‐school earnings have increased to $300 per month. What is the percent increase in his monthly after‐school earnings?

First, circle what you're looking for— *percent increase.* Percent change (percent increase, percentage rise, % difference, percent decrease, and so forth) is always found by using the equation

Therefore,

The percent increase in Harold's after‐school salary is 20%.