Subtract to find the amount of change.

New measurement original measurement

18 45

= 27                 (Subtract: 18 45 = 27)

Write a ratio that compares the amount of change to the original amount.Express the ratio as a percent.

Percent change = .

              (Divide: )

Write decimal as percent.

Multiply by 100 and add .

            (Multiply: )

The percent of change is about .In this case, the percent of change is a percent of decrease.