Percentage Increase and Decrease

Percentage strips can also be used to answer percent increase and decrease problems. The percentage strip method is shown below to demonstrate how percent increase and decrease problems can be solved in one step.

Example: A rancher purchases pigs. Six months later, some of his female pigs have had piglets and now the total number of pigs that he owns has increased by 50% .

Make one percent strip that represents 100% and make a second strip cut to represent 50%. Lay the strips next to each other.

 10% 10% 10% 10% 10% 10% 10% 10% 10% 10%
 10% 10% 10% 10% 10%
1. What does the first strip represent?
2. What does the second strip represent?
3. What do both strips together represent?

This model represents 100% and 50% of a quantity, which is the same as 150% of that quantity.

1. Use percentage strips to find a 50% increase of 424.   Verify your solution using an equation.
2. Use percentage strips to find a 40% decrease of 36.  Verify your solution using an equation.

Check solutions here.