Using Bar Models To Solve Complex Multi Step Problems

Hi, I'm Zoe. And in this video we're going to be looking at how we can solve complex multi step problems using our bar model. With these questions, we're looking at our upper key stage two. It's a really good idea to get them to read through the question at least twice to get a grips with what's there. So Zainab spent five times as much as Josh in the shop. Zainab paid with a 20 pound note. A received 1 pound 95 change. How much did Josh spend? So we're going to start with what we know. We're starting with a bar and what we know is Zinab paid with a £20 note. So this bar represents what Zainab used to pay. So we've got a £20 note. What do we know next? One pound ninety five was given in change. Going to put that at this end. £1 95. At this point, it's a really good idea to ask the pupils what this part of the bar represents. Gives them a good understanding, hopefully that that is the money that Zainab has spent. So we can label this bar with what has been spent. Now they hopefully can see that we need to subtract the £1.95 from the £20 to find out how much that was. We can either use that with a formal written method or a good way is to take away two pounds and add five pence on enhancing those mental skills. So hopefully the pupils work out. That is £18 and 5 pence that was spent. Now, going back to the question, we've used the bits we know. This first part we haven't used yet. Zainab spent five times as much as Josh. Using that inverse relationship, Zainab spent five times as much, means Josh spent a fifth of what Zainab spent. So looking at our bar, we're going to divide this into five equal blocks. So starting trying to be as accurate as possible, but getting the proportions about right. So each one of these blocks is a fifth of what Zainab spent. So one of these blocks what Josh spent. So now hopefully they can see that what we've got to do is divide £18.05 by five using again one of the written methods or one of our mental methods to do that. And they should arrive at the sum of £3 61 going back into our bar. We can fill that in. We could also fill these in and check that that added up to 18 pound 5. Another good way of really embedding this is to use actual money, to use money to put into here so that the pupils get a real idea of mixing the concrete with the abstract. And that's how to use our bar model when we're looking at really complex multi step problems.