Teach The Grid Method For Multiplication Of Two Digit Numbers By Two Digit Numbers

Hi, I'm Felicity and today we're going to be looking at using the grid method to multiply two two digit numbers together. So let's have a look at this example. In a school hall there are 32 rows with 16 chairs per row. And we want to figure out how many chairs there are in total in the hall. So let's use our grid method to help us. Now previously we might have used pictorial methods to help us work out our answer. And that's fine with smaller numbers to draw counters or use dots, but with these two two digit numbers it's simply not practical to draw row upon row of dots. So we're going to rely on the children's knowledge of place value and they're going to be able to times the numbers by 10. I'm also going to make it a little bit simpler by partitioning our values into tens and into ones. So 32 becomes 30 and 2, 16 is partitioned into 10 and 6. So first of all we're going to times 10 by 2, which will give us the value of 20. And we write that in here in the grid and then we're going to times 10 by 30, which we know equals 300. Now we need to do the same over here. So we need to times 6 by 2 to give us 12 and we need to multiply 6 by 30, which gives us 180. Now we need to total all these together. So let's start with the ones we can see that we've got, 32. And then when we add 300 to 180, we have 480, which means our final answer is going to be 480 plus 32, which gives us a total of 512. So in the school hall there are 512 chairs in total. And that's how you can use the grid method to multiply two two digit number.