Pre-Algebra: Lesson 103

Percent Problems
Percent Increase or Decrease

Lesson Description

Students learn to find the percent increase or percent decrease between two numbers, using the following formula: amount of change/ original number. For example, to find the percent decrease if the price changes from $60 to $39, since the amount of change is $21, and the original number is $60, the percent decrease is $21/$60, which simplifies to 0.35. And remember that the answer is a percent, so move the decimal point two places to the right, to get 35%. So if the price changes from $60 to $39, the percent decrease is 35%.

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