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 Question from Amy, a student: what is the easiest way to remember how to do percents?

Hi Amy.

Just remember that percent means "per hundred" (there are a hundred cents in a dollar right?) That means a fraction.

So 90% means the fraction 90/100.

When you take a percentage of something, you multiply it by that number over 100. For example, the tax on my new computer is 5% of $800. That means I have to pay 800 x 5/100 =$40 tax !

Some people are better with decimals than fractions, and you could certainly use that instead. Just remember that you move the decimal point two places to the left. 90% = 0.90 and 5% = 0.05. Then using the same example as above, 5% of $800 is 800 x 0.05 =$40, just the same.

Use whichever way is easiest for you to remember, but the easiest in my opinion is remembering that "percent" means "per hundred".

Cheers,
Stephen La Rocque.

Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.