Lesson video

Hello, my name is Mrs Behan and for this lesson, I will be your teacher.

We are going to learn how to divide a two digit number by a one digit number.

We're going to use dienes or base ten to help us.

So we're going to learn how to draw that out.

We're going to use a partitioning and recombining method as well.

So when you're ready, let's begin.

So let's start by having a look at the lesson agenda.

We are going to represent dienes with drawings.

Then I'm going to teach you how to partition to divide.

We will then have a practise activity.

There will then be an independent task for you to have a go at.

And I know you will be keen to find out how you got on.

So I will make sure that I go through the answers with you.

For this lesson there's just two things that you're going to need.

Something to write with, so a pencil or pen and something to write on.

If you don't have those things handy, just pause the video now and just to go and get them.

And remember, try to work somewhere quiet where you're not going to be disturbed for the lesson.

So let's have a look at how we can represent hundreds, tens and ones using drawings.

This is what we normally see.

This is what dienes or base 10 look like.

But when I draw them to help me do my calculations, here we go, I do some sort of square for a hundreds, a stick for a 10 and a dot for a one.

They don't need to be exact, they don't need to be pretty because they're just a jotting to help us work out our calculations.

So for example, 123 would be represented as one, 100 two sticks for the two tens and three dots for three ones.

Let's see if you can have a goal, at representing some numbers using these drawings.

So write these numbers down on your piece of paper and then draw the base 10.

Remember some sort of square for a hundred, a stick for a 10 and then a dot for a one.

When you've finished the left hand side of your screen, have a look at the right hand side.

You going to do the opposite for this one.

What is the value of the base 10 or dienes that you can see on the screen? There are four different sets.

Pause the video here whilst you have a go at this activity.

When you're ready, come back to me.

Take as long as you need.

Okay then, I'm going to flash up the images or the representations that I had done.

So 23 has got two tens and three ones in it.

124 has got 100 block, two tens and four ones.

65 has got six tens and five ones in it.

And 216 is represented with two, 100 blocks, one 10 and six ones.

130 is a bit of a tricky one.

We have a zero as a placeholder for ones.

So we just have one, 100 block and three tens.

We don't need to do anything for the ones and 102 is something similar.

We need one, 100 block, zero tens and two ones.

Our zero is in the tens place as a placeholder.

So what's the value of this section over here? So the first one, the value is four tens and five ones, which is 45.

We then have 183, 107.

The tricky part here was remembering to put the zero for the tens placeholder and again we need a zero in the tens placeholder.

There are zero tens, 303.

Well done.

So in this lesson, we're going to be dividing a two digit number by a one digit number.

It's really important that we know the correct vocabulary for each of the numbers in a division equation.

So let's have a little look.

So in this example, you can see six divided by two is equal to three.

Can you remember the name of this number here? This number is called the dividend.

Can you remember the name of this one? This has the job of grouping or sharing.

This is the divisor.

And can you remember the name of this number here after the equal sign? This is the quotient.

So we have dividend, divisor and quotient.

Oh, I've got a missing word here.

Something is the inverse of division.

Which operation is the inverse of division? That's right, multiplication is the inverse of division because we are going to be dividing, We can use the investor to check our answers.

So we may well use some multiplication today to check our calculations.

Okay, then this is a drawing of the Silverstone race track.

Did you know that Silverstone is the British race track? Lewis Hamilton is a famous race car driver and he has won many many races at Silverstone men's track.

Let's say that we wanted to go and watch him race.

It costs 64 pounds for two tickets to the race at Silverstone.

So how much does each ticket cost? So let's think about how we're going to work this out.

It costs 64 pounds for two tickets to the race at Silverstone, how much does each ticket cost? To find the cost of each of the tickets, we need to divide 64 by two.

So we're going to use our partitioning skills to do this.

If we partition 64, we end up with six tens or 60 and four ones.

Now each of those numbers now needs to be divided by two.

So we will calculate 60 divided by two and four divided by two.

Let's have a look.

We can see six tens over here, 60 divided by two.

So I've got two groups to share them into.

Three tens goes in one group and three tens goes in the other group and now have two equal groups of 30.

So 60 divided by two is equal to 30.

So let's divide the ones.

Four divided by two is equal to, I'm sure you know this.

Two in that group, two in the other group.

So in each group, there are two.

Say that with me, four divided by two is equal to two.

So what is 64 divided by two? Well we've already partitioned, so now let's recombine.

So here are our groups.

There are two groups each with three tens and two ones in each group.

So I'll put that together and it's 32.

So 64 divided by two is equal to 32.

What does that tell us about the cost of each ticket? Well, each ticket costs 32 pounds.

So we can go to the races for 32 pounds each.

So how do we get to that answer then? So all we did was we partitioned the dividend.

Remember the first number in our division calculation is the dividend.

We partitioned it into tens and ones.

We then divided the tens by the divisor.

So we're in our example, the devisor was two.

So we had to divide the tens by two.

We then divided the ones by the divisor.

Again, in our example it was by two.

And then once we've done that, we recombined the parts.

This calculation has a missing number.

Is it the dividend, the divisor or the quotient? Yes, it's the quotient that's missing.

So here are some options to find the missing number.

Option one.

Is it 69, option two 13, option three 18 or option four 12.

So as a reminder to work it out, you will partition the dividend, divide the tens by the divisor, which in this case is three, divide the ones by the divisor and then recombine the two parts that you have made.

Pause the video here whilst you have to go and work it out.

And when you're ready, come back to me.

Are you ready? Let's have a look through it.

Option one, 69.

Is that correct? No, there's no connection there between 36 and 69.

Option two is incorrect as well.

If you divide it by three, you would not have got 13.

Option three is wrong.

There is a connection with 36 but we would have to do 36 divided by two because half of 36 or 36 divided by two is equal to 18.

So that means that our correct answer is 12.

So let's have a look at why the quotient was 12.

Here's our calculation.

36 divided by three is equal to 12.

So I partitioned 36 into three tens and six ones, divided them or shared them between three groups and I got something that looks like this.

I've used my drawings to represent the dienes.

So you can see there is one 10 in each group and there are two ones in each group.

I can use multiplication to check.

Now, I already know the number fact, 12 multiplied by three is equal to 36.

So now I'm spot on with my quotient being 12.

I can use a place value charts to represent my calculation too.

So this is how I would do it.

Each row represents a group and I have three rows because my divisor is three.

So I'm now going to partition again, my 36 into three tens and six ones and put them into the place value chart.

Have a look.

So I shared out my three tens, one 10, two 10, three tens and then I shared out my six ones.

I could put two in this box, two in this box, two in this box and you can say how many is on each row.

That's right, 12.

So it's just another way of looking at it.

Instead of drawing out groups like this, I can use a place value chart.

You've got enough information now to be able to have a go at the independent task.

I'd like you to draw out a place value chart for each calculation and represent your tens and ones with drawings.

So here is an example.

So I have divided 24 by two and it's meant that I have 12.

The divisor is the number of rows.

Remember? So I've got two rows ready.

Partition 24 into tens and ones.

So that means I have two tens and I've put one in each row and then I divide the ones, so four divided by two, means I can put two on each row.

So when I recombine a look at it together in each row, there are 12.

Have a go, drawing out a place value chart for each of these calculations.

Pause the video here to have a go at the task.

When you're ready, come back to me and we'll go through the answers together.

Okay.

How did you get them? Let's have a look.

26 divided by two is equal to 13 because 20 divided by two is 10, six divided by two is three, recombine 10 and three and you have 13.

48 divided by two is equal to 24.

40 divided by two is 20, 8 divided by two is four, recombine them and you have 24.

30 divided by three is equal to 10.

We don't need to partition here because there are zero ones.

So three tens shared between three is just 10.

39 divided by three is equal to 13 because 30 divided by three is equal to 10, nine divided by three is equal to three, recombine 10 and three and you have 13.

44 divided by four is equal to 11, 40 divided by four is equal to 10, four divided by four is equal to one, recombine 10 and one and it makes 11.

50 divided by five is equal to 10.

This is similar to have 30 divided by three calculation.

We have zero ones here, so we only need to share out the tens.

So 50 divided by five is equal to 10.

63 divided by three is equal to 21 because 60 divided by three is equal to 20, three divided by three is equal to one, recombine 20 and one and it makes 21.

66 divided by three is equal to 22 because 60 divided by three is equal to 20 and six divided by three is equal to two.

So recombine them and we have 22.

If you'd like to, please ask your parents or carer to share your work on Instagram, Facebook or Twitter tagging @OakNational, @LauraBehan21 and #LearnwithOak.

What a super successful lesson dividing two digit numbers by one digit numbers using partitioning and recombining.

Take the quiz to test out your new learning.

See you again soon.

Bye bye.