How to use the other formula for percentage on the right. 1000 800. To calculate the percentage of a specific number you first convert the percentage number to a decimal.
Step 1 Get the percentage of the original number.
X 03x 420. This process is the reverse of what you did earlier. Original price 30original price sale price. If the percentage is an increase then add it to 100 if it is a decrease then subtract it from 100.