Hi, my name is Marija. I'm a mathematician and today I'm going to show you how to teach kids how to simplify fractions. So, if you have a fraction like ten over thirty, your goal is to find the greatest number that can go into both ten and thirty. What is the greatest common factor of ten and thirty? And when you find that number, you're going to multiply the numerator and denominator by it. So, the biggest number that can go into ten and thirty is ten. So, I'm going to do division by ten in the numerator, and division by ten in the denominator. And when I do that, I get ten divided by ten is one, and I get thirty divided by ten is three. So, ten over thirty reduces to one-third. Now, if you can't think of the greatest common factor right away, but you can think of a common factor--let's say you know that ten and thirty are both even. So, they're both divisible by two. You can start by dividing top and bottom by two. So, I'm going to divide the numerator by two, and divide the denominator by two. Ten divided by two is five, and thirty divided by two is fifteen. But now you have to ask yourself, is there another number that can go into five and fifteen? And there is. Five can go into both of them. So, I'm going to divide again. I'm going to divide numerator and denominator by five. So, five divided by five is one, and fifteen divided by five is three. So, I arrive at the same answer. It just took me an extra step because I didn't use the greatest common factor here. So, either way you do it, you will result in the same simplified fraction. My name is Marija, and I just showed you how to teach kids to simplify fractions.