Mastering Percentage Increase and Decrease

Mastering Percentage Increase and Decrease

Learning Objective

At the end of the lesson, you will be able to calculate percentage increase and decrease.

What do you already know about percentages?

What is Percentage?

Percentage is a way to express a fraction or a part of something out of 100.

Percentage Increase

Percentage increase is the amount of increase expressed as a percentage of the original value.

Calculating Percentage Increase

To calculate percentage increase, subtract the original value from the new value, divide by the original value, and multiply by 100.

Percentage Decrease

Percentage decrease is the amount of decrease expressed as a percentage of the original value.

Calculating Percentage Decrease

To calculate percentage decrease, subtract the new value from the original value, divide by the original value, and multiply by 100.

Interactive Practice

Solve the following problem: A shirt originally priced at $50 is now on sale for $40. What is the percentage decrease?

Summary

Percentage increase and decrease are useful concepts for understanding changes in values. Remember to use the correct formulas when calculating percentages.

Write down 3 things you learned in this lesson.

Have students enter three things they learned in this lesson. With this they can indicate their own learning efficiency of this lesson.

Write down 2 things you want to know more about.

Here, students enter two things they would like to know more about. This not only increases involvement, but also gives them more ownership.

Ask 1 question about something you haven't quite understood yet.

The students indicate here (in question form) with which part of the material they still have difficulty. For the teacher, this not only provides insight into the extent to which the students understand/master the material, but also a good starting point for the next lesson.