Finding the Percent of Increase or Decrease

Property $$\frac{\text{amount of increase or decrease}}{\text{original amount}} = \text{Percent of change}$$.

Examples From 200 students to 250: The increase is $250 200 = 50$. The percent increase is $\frac{50}{200} = 0.25$, or $25\%$. From 80 dollars to 60 dollars: The decrease is $80 60 = 20$. The percent decrease is $\frac{20}{80} = 0.25$, or $25\%$.

Explanation First, find the difference between the new and original numbers to find the amount of change. If the new number is bigger, you've got an increase! Then, just divide that change by the original amount and multiply by 100 to get your percentage. It's the perfect way to track growth or shrinkage in numbers!