Using talking partners and building on students’ answers to solve a mathematical problem using the interactive whiteboard at a primary school

Teacher: 75% of something - we don’t know what the original price was - equals £345. Have a talk with your partner, how are you going to solve that? how are you going to solve that?

Teacher: And, so talk me through it. Erm, right, I'll begin, I'll begin, I'll begin. ((Writes 75/100 on the interactive whiteboard)).

Student 1: No, Sir.

Teacher: No?

Class: No, no ((several hands raised))

Teacher: No? Why not? It's out of 100. 75% out of 100. I don't understand. Er, someone to help me. Jennifer H.

Jennifer H: Three quarters.

Teacher: Three quarters. So you're saying you know that's an equivalent fraction. Why not use 75 over 100?

Jennifer H: You can but it's going to take a bit longer.

Teacher: It's going to be harder. So the intelligent, the sensible, we don't want harder. We want easier ((deletes '75/100' from interactive whiteboard)).

Nilafa: It's three quarters.

Teacher: OK. Don't call out, Nilafa, 'cos I was talking to Jennifer. Make sure the hand goes up. ((Writes '3/4 of', then draws box, then writes '=£345' on the interactive whiteboard)) Three-quarters of something equals 300- I'm rewriting this statement every time so I'm clear what it means. Somebody talk me through our strategy now, 'cos we've got strategies for solving these missing number problems, haven't we? ((Several hands raised)) OK, er... let's pick on somebody. I want more contribution from Zisham.

Zisham: So, normally you'd do 0.5 divided by (inaudible) x 4.

Teacher: So I'd do the inverse operation I mean the opposite, because I'm not finding - let's be clear and this is what most people set off to do - I'm not finding three-quarters of 345 ((indicating to interactive whiteboard)). I'm finding three-quarters of something that equals 345, and the quick way of doing that, we talked about strategies to speed up, is to do the inverse operation; do the opposite. So somebody talk me through that? ((Several hands raised)) OK, first step is, er ((looking round classroom))... Leanna.

Leanna: 4 x 345.

Teacher: 4 x 345. OK, let's do that. 4 x 345 ((writes '4 x 345' on interactive whiteboard)). OK, strategies for doing this. ((Several hands raised))… OK, Abdul, your strategy.

Abdul: Sir, I couldn't do that mentally, so I did it vertically.

Teacher: Talk me through the vertical method. Notice that he acknowledges there is a way of doing it mentally, and there maybe are a couple of people who might be able to do that and explain how. Talk me through it.

Abdul: 345- ((T Writes '345' on the interactive whiteboard)) and then the 4 under the 5. ((T writes '4' on the interactive whiteboard with a line underneath)) Then 5 x 4 equals 20, put the 0 there and carry the 2, 4 x 4 is 16, add the 2 is 18, 8 and carry the 1, 4 x 3 is 12, add the 1, is 13. (Inaudible).

Teacher: ((Writing on the interactive whiteboard)) So the answer is?

Abdul: 1280 because (inaudible).

Teacher: Right, so there's more steps to do.

Abdul: Yes.

Teacher: OK. Just out of interest, is there anybody who can do that mentally?… Saffron, talk us through what happens. Saffron has developed more than two places to store a number. He's obviously developed three places to store a number. So let's see if you can have a practice of what he does. Let's have a go, see if you can do the same thing. Step 1.