You might have been in fifth grade the last time you thought about multiplying fractions. But if you're trying to cut a recipe in half or calculate the new price of a sale sweater using fractions, you might need to dig around in the back of your memory for how to do it. Let's refresh:

In every fraction, there's a top number and a bottom number, separated by a short horizontal line. In a proper fraction, the smaller number — called the numerator — will always be on top, while the larger number — the denominator — will be on the bottom. The numerator tells us how many units we have of a whole and the denominator tells us how many units make up the whole. So, in the fraction 1/2, *1* is the numerator and *2* is the denominator — there are two units in the whole, but this fraction tells us that we only have one of these units.

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Unlike when you are adding or subtracting fractions, you can multiply fractions with different denominators. For instance, it's not a problem to multiply 3/4 x 2/5.