Percentage change
for 8th grade

How to calculate percentage change

To compare two quantities and work out the percentage increase or decrease, follow these steps:

Step 1: Calculate the difference between the two quantities.

Subtract the initial quantity from the final quantity to find the difference. For example, if the temperature of a liquid started at 50° and increased to 60°, the difference is 10°.

Step 2: Divide the difference by the original quantity and multiply by 100.

To find the percentage increase or decrease, divide the difference by the original quantity and multiply by 100. If the difference is positive, it is a percentage increase, and if the difference is negative, it is a percentage decrease. For example, if the initial temperature is 50°, then the percentage increase would be:

Difference = 60° - 50° = 10°

Percentage increase = (10/50) x 100 = 20%

Therefore, the temperature increased by 20%.

So, to compare two quantities and work out the percentage increase or decrease, you need to calculate the difference between the two quantities, divide the difference by the original quantity, multiply by 100, and include the percent sign in the answer.