How to Divide Fractions
Question
In the fraction 7/8,
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Hi, my name is Bassem Saad and I'm a Math Ph.D. candidate at U.C. Davis, and I'm here today for About.com to show you how to divide fractions.Remember, a fraction is made of a numerator and denominator, with the numerator on top and the denominator at the bottom. For example, in the fraction 7/8, the seven is the numerator and the eight is the denominator.Let's take a look at an example: 3/5 divided by 7/2. The first thing you need to do is flip the right-most fraction, so 7/2 becomes 2/7. Then you change your division symbol into a multiplication symbol. So now you have 3/5 times 2/7. You multiply across the top to get your numerator; three times two is six. And you multiply across the bottom to get your denominator; five times seven is 35. Now we know that 3/5 divided by 7/2 equals 6/35.Let's take a look at another example; 2/5 divided by 4/5. So again, we flip the right-most fraction so that 4/5 becomes 5/4, and we change the division symbol into multiplication. So now we have 2/5 times 5/4. You multiply across the top to get ten, and you multiply across the bottom to get 20. Now we can further simplify by first noticing that the numerator and the denominator have a greatest common divisor of ten. So we divide ten into the numerator to get one, and ten into the denominator to get two. So now we know that 2/5 divided by 4/5 equals 1/2.So let's talk about applications. You may be wondering, “When will I ever use this in my daily life?” For those of you who want a career in the culinary arts, you will most definitely need to know how to divide fractions. Scientists, as well as medical professions, also divide fractions on a daily basis. And those of you who like to sew – knowing how to divide fractions will come in handy.Thanks for watching, and to learn more, visit us on the web at About.com.