How to Increase a Number by a Percentage

Some word problems in math class will ask you to increase a number by a percentage. Or, even in day to day life you may want to know about cost or population increases. Here is some handy math.

Things You'll Need

• Calculator

Instructions

1. Start with a number. You can do this with any number. We will chose 100 in this example to make it easy.

2. Find the amount of the increase. If it is a word problem, it may state something similar to "the cost went up 25%".

3. Change the percent to a decimal. Turn 25% into .25.

4. Multiply the amount of increase by the original number. Our example is 100 and 25%, so multiply 100 by .25, which equals 25. (100)(.25) = 25.

5. The new number is the original number (100) plus the increase (25). 100+25 = 125.

6. 

   You can always see how much a number decreases by a percentage. Follow steps 1-4 and then subtract the number. Example: If it is a 25% DECREASE, you would subtract 25. 100-25 = 75.

7. Apply to word problem or situation. So, if a if a $100 item increases 25%, the new cost would be $125.

Tips & Warnings

• Use a calculator to avoid mistakes.