# Lesson video

In progress...

Hello and welcome to today's lesson, my name's Miss Thomas, I'll be going through the lesson with you today.

We've got some really exciting learning coming up.

We're looking at how we can use known multiplication facts to divide.

Which we can do a lot that mentally.

So we'll get some really good helpful strategies today.

Before we start though I want to show you something really cool, so this is a pop up card.

That somebody I know made and it's like a lily flower inside.

Well, not so much like a.

Well kind of like a waterbed lily.

How exciting is that? Okay, well let's get started with our maths for today.

In today's lesson first we'll be partitioning numbers to divide mentally, then we'll go to talk task, where you can have a practise.

After that we'll be using known multiplication facts to divide mentally and finally you'll finish with your end of lesson quiz.

The equipment you will need for this lesson is a pencil, paper and a ruler.

Pause video now if you need to gather your equipment.

Let's get started.

Question says how many groups of 6 are in 78? And the equation for that is, 78 divided by 6.

We're trying to find out how many groups of 6 are in 78.

Well I could use my counters to do that, so I've got 78 blue counters here and I can group them all into sixes, to see how many groups of 6 I've got.

If I take out 6 counters and I put them in a group and I'll take out another 6 counters and I'll put them in a group.

You might of said this will take me a long time and if I had a greater number than 78, it would take me even longer.

I would not be able to solve this quickly so it's not really an efficient method.

What multiples of 6 are in 78, that we know? Well, I know that 60 and 18 are multiples of 6 and 78, let's see how we could use our multiples to help us.

So we know that 60 and 18 are multiples of 6 and 78, okay let's have a look at how we can use that.

Well I know that 6 multiplied by 10 is equal to 60, so I know that there are 10 groups of 6 in 60.

I know that 6 multiplied by 3 is 18, so therefore I know there are 3 groups of 6 in 18.

I can then add how many groups of 6 are in 60, so I can add 10 plus the three groups of 6 that are in 18, so 10 plus 3 which is equal to 13.

So I know that there are 13 groups of 6 in 78, 78 divided by 6 is equal to 13.

Let's have a look at another one, let's do this one together.

The question says first, what multiples of 4 do we know? Can you call out some multiples of 4 to your screen please? Great, I'm sure lots of you said multiples of 4 that are in the times table we know up to 12.

What multiples of 4 could we partition 432 into? This time you might need to derive some facts as well as using your known facts.

Pause the video and have a go at finding multiples of 4 that we could use to partition 432 into.

Great, I'm sure you've found a way, I'm going to show you the way that I did it and if you did it differently that's absolutely fine.

So I partitioned 432 into 400 and 32.

I'm going to derive some facts about 400, so I know that 4 times 10 is equal to 40, so I know that 4 times 100 is 10 times greater.

So my products 40 will be 10 times greater, it will be 400.

So I know that there are a 100 groups of 4 in 400.

Let's take a look at 32.

4 multiplied by 8 is equal to 32, so I know that there are 8 groups of 4 in 32.

100 groups of 4 in 400 and 8 groups of 4 in 32.

So the last thing to do is add the number of groups of 4 there are, so 100 plus 8 is equal to 108.

So I know that there are 108 groups of 4 in 432, 432 divided by 4 is equal to 108.

Let's take a look at the next one, you need to decide what multiples of 6 do we know and what multiples of 6 could we partition 372 into.

Pause the video and decide.

Welcome back, I'm sure you found a way, so the way that I did it is I partition 372 into 300 and 72.

So with my 300 I'm going to use my derived facts, I know that 6 times 5 is equal to 30, so I know that 6 multiplied by 50 is equal to 300.

It's 10 times greater, 50 is 10 times greater than 5, so my answer will be 10 times greater than 30 will be 300.

So I know that there are 50 groups of 6 in 300.

Let's take a look at the 72, I know that 6 multiplied by 12 is 72.

So I know that there are 12 groups of 6 in 72, there are 50 groups of 6 in 300 and there are 12 groups of 6 in 72.

So now I need to add the number groups of 6, so 50 plus 12 which is equal to 62, so I know that there are 62 groups of 6 in 372.

372 divided by 6 is equal to 62.

Using your known multiplication facts solve the equations, use jottings to record the steps of your divisions.

What are the fewest number of steps, you can use? So often we think of the fewest number of steps, the most efficient way, because its quicker.

So you've got the equation 545 divided by 5 and 927 divided by 3.

Use the sentence stems to explain out loud your thinking, once you've solved the equations.

Welcome back, we've got our answers here, so we know that 545 divided by 5 is equal to 109 and we know that 927 divided by 3 is equal to 309.

There are many ways you could have solved these equations, hopefully you tried to use the sentence stems to explain out loud your method.

If you didn't do this yet pause the video and have a go, hopefully you found methods that didn't require lots of steps to solve it.

These are the most efficient methods for the equation.

Okay next were going to be dividing on a number line, to find how many groups of 6 are in 324.

So we want, 324 I'm going to think back my known facts.

well first of all I know that 6 multiplied by 50 is 300 because I know that 6 times 5 is 30, 6 times 50 is going to be 10 times greater.

So I'm going to take my 300 on my number line to get to 24, so I know that there are 50 groups of 6 in 300.

Now I need to go from 24 down to 0, so I know that 6 multiplied by 4 is equal to 24, so I can take away 24.

So I know that there are 4 groups of 6 in 24 and that will take me to 0.

The final step is to add how many groups of 6 are in 24 and how many groups of 6 are in 300.

So 50 plus 4 is equal to 54, I know that 324 divided by 6 is equal to 54, I've used my known multiplication facts to divide 324 by 6.

Let's take a look at the next one, we'll do this one together.

824 divided by 4, so we're going to have our number line, with 824 at the end and we want to get down to 0, using our known multiplication facts.

Can you shout out a fact that you think we could use to help us? Call out your answer.

Great, there are many you could have said, the one that I'm going to choose is that we know that 4 multiples by 200 is 800 because we know that 4 times 2 is equal to 8, so we can use our derived facts 200 is a one hundred times greater, so our answer 8 will be one hundred times greater it will be 800.

And that will take us all the way down, we'll have to take away 800 and it will take us all the way down to 24.

Next we need to get from 24 to 4, could you divide 24 divided by 4, what would that give you? Call out your answer.

You might have used your known fact, of 4 multiplied by 6 is 24, so 24 divided by 4 is equal to 6.

So you can take away 24 that will take us to 0, so we know that there are 6 groups of 4 in 24 and that there are 200 groups of 4 in 800.

So the final thing we add how many groups of 4 are in 800 and how many groups of 4 are in 24.

So 200 plus 6 is 206, 824 divided by 4 is equal to 206.

Here we've got Tia and Joe working it out, you've got to decide what's the same and what's different.

Pause the video and explain your thinking out loud to your screen.

Welcome back, you might have found that what's the same is that Tia and Joe are both solving the equation to 824 divided by 4 and both children got the same answer of 206.

However you might have found that they've used different know and derived facts to get their answers and Tia she's calculated hers in two steps and Joe he's calculated his in four different steps.

We can use different know facts to derive and to get the same answer, so both children have got it correct.

Now you've reached your independent task, for each question you need to do number 1, number 2 and number 3, so number 1, what's the fewest number of jumps you can complete it in? Number 2, can you complete it in an even number of jumps? Number 3, can you complete it in and odd number of jumps? So you might want to partition your number, you could have a go on the number line, have a go at solving the equations.