How To Add And Subtract Improper Fractions

Hi, my name is Brooke, and in this video we're going to be adding and subtracting improper fractions. So let's have a look at our first example. Four thirds, add seven thirds. Now, you'll notice that the denominators are the same, so we can add them straight away. 4 thirds, add 7 thirds is 11 thirds. In this example, the denominators are different, but they're related. So we simply need to find an equivalent fraction that has a denominator of 4. And to do this, I'm going to split my halves into quarters. So now we'll see that I've got 10 quarters and I can add that to my five quarters to give 15 quarters. Now, in this example we're subtracting fractions that have unrelated denominators. So, so we need to find a common denominator, and to do that we find the lowest common multiple, which is 15. So I want each of my fractions to have a denominator of 15, and to do that, I'm going to find an equivalent fraction. So an equivalent fraction to 7/3 would be 35, 15, and an equivalent fraction to 6/5 would be 18, 15. And now that the denominators are the same, I can subtract them. So 35, 15, take away 1815 equals 6, 17, 15. And that's how you add and subtract improper fractions.