How To Multiply Proper Fractions By A Whole Number

Hi, I'm Rebecca, and in this film we're going to look at how to multiply fractions by whole numbers. Now, this is a concept that children find really hard to grasp, so it's really important to give them lots of different representations to practice this. So let's take a calculation, four times a half. Now, at this stage, you want children to be doing this and exploring it. So here I have some pizza tiles that children can actually manipulate to put together to show that four times a half will equal two. We can also do this on a number line by doing jumps of a half, four times half, one, one and a half and two. And counting on a number line in fractions like this is really important for children. Now, for the written method here, we can turn four into four ones and write it as an improper fraction. Then we can multiply the numerator 4 times 1 is 4 and the denominator 1 times 2 is 2. And then we can turn that into a mixed number, which we know is two. Let's look at a different example. Here I have five times a third, and this time I've got two bar models and they're split into thirds, and I'm going to shade them in thirds until I've done this five times. And then you can really clearly see that that gives us one whole one and two thirds. Again, we're going to go back to our number line, and this time I've got a numbered number line and I'm going to do five jumps of a third. One, two, three. At this point, I'm going to stop and make sure that children understand that when you get to three thirds, it's equal to one whole, and then another two thirds, one, two, to give us one and two thirds. And then finally our written method, five ones. So five over one. Five times one is five, one times three is three. Our improper fraction can be turned into a mixed number, which we now know is one and two thirds. So there's lots of different representations to help children understand how to multiply fractions by a whole number.