How to calculate the percent of change (percent of increase or decrease)

This is a beginner lesson explaining how to calculate the percentage of change. We simply find the actual DIFFERENCE between the original and the new quantities, and divide that by the original quantity. In other words, we write the fraction DIFFERENCE/ORIGINAL, or compare the actual change to the original amount. Then all you do is write that fraction as a percentage (possibly first changing it to a decimal with a calculator, and then from a decimal to a percentage).

See also

Percent of increase/decrease: write an equation to solve for the original price — video lesson

Math Mammoth Grade 7 curriculum (pre-algebra)

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