Using Bar Models To Solve Challenging Multiplication Problems

Hi, I'm Ellie and in this video we're going to be looking at using bar modelling to solve a more complex multi step problem. So let's look at the problem that we have on our board. Fiona won five times as many games of Snap as Luke. Luke won half as many games as Shelley. Altogether they won 72 games. And how many games did Fiona win? So this is an example of a comparative problem. We're going to look at the number of games each of them won to try and solve the problem. So let's look at the information that we have. To begin with, you'd want to get your pupils to read the question through again and they can underline the important bits of information. We're then going to apply that information to our bar model. So I'm going to start with Luke. So Luke won a number of games. At the moment we don't know how many games that is, but I'm going to draw this and we'll get to our answer in a bit. It then tells me Fiona won five times as many games of Snap as Luke. So because I know that Fiona won five times as many, I can draw that bar for Fiona five times bigger than Luke's. So it's important that you draw that in the same size as that initial bar, but we're going to draw it five times to represent the five times as many games that she won. Okay, so this is Fiona's bar showing how many games she won. And then the last person that we need to mark down is Shelley. So what do I know about Shelley? Luke won half as many games as Shelley. So using the inverse, your pupil should be able to tell you that if Luke won half as many games as Shelley, that means that Shelley won twice as many games as Luke. So here I've got Shelley's bar and I'm going to draw it twice as long as Luke's bar. Okay. And there's one other bit of information that we have in our question which we need to use and that is that all together they won 72 games. So let's mark that here, 72 games. And now your pupils should be able to see that because they've got eight equal parts altogether. To find out how many games this is, they just need to divide 72 by 8. So 72 divided by 8, which we know is 9. So we can say straight away that we know that Luke won nine games. Pupils shouldn't stop there though. We need to go back to the question, what did it ask them to do? Altogether they won 72 games. How many did Fiona win? So here we need to look at this bar here and you need to ask pupils, how can I work out how many games Fiona won? And they should be able to tell you that because there are five equal parts in Fiona's bar, they just need to do nine times by five. So nine times by five, which will give you 45. So they can tell you that Fiona won 45 games of Snap. And that's how we can use bar modelling to solve a more complex problem.