Lesson video

Hello everyone, my name is Miss Sabzvari, and I'm really excited you decided to join me today for our math lesson.

The unit we're studying is multiplication and division.

In the previous lesson, we looked at how to use the division symbol when sharing.

In this lesson, we will focus on using the division symbol when grouping.

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

Let's have a look at today's lesson agenda.

First, we'll begin by looking at division as grouping.

Then we will move on to a talk task, where you will get more opportunities to use a division symbol when grouping.

Alongside this we will discuss whether division is commutative.

And finally, you will complete your independent task.

Before we begin the lesson, you will need the following items. You will need something to write with and something to write on, and you will need some cubes or counters.

Alternatively, you can ask your parent or carer to cut out some small pieces of paper that you can use instead.

So pause the video now and get the items that you need.

Division as grouping.

Let's have look at the word problem on our screen.

Follow with me.

There are 24 children.

Children sit in rows of six.

How many rows will there be? What I would like you to do is to pause the video, and tell your screen what is known and what is unknown.

Great work.

We know the whole, so we know that there are 24 children, and we know how many are in each group.

We know that there are six children in each row.

But what we don't know is how many rows we are going to have.

So let's have a look at my diagrams, which show us the difference between division, or dividing, by sharing and dividing by grouping.

In the previous lesson, we discussed that when we are dividing by sharing, we know the value of the whole.

So we know how many children there are all together, so, in this case, we know that there are 24; and we know how many parts there are.

That means how many rows there are going to be.

But what we don't know is the value of each part.

We don't know how many children are going to be in each row.

In this instance, for our question that we're looking at today, we know that we are dividing by grouping, because we still know the value of the whole, we know how many children there are all together.

How many children, tell your screen.

Good work, 24.

But we also know the value of the parts.

That means we know how many children are going to be sitting in each row.

But what we don't know is how many parts there are.

So our job is to work out how many rows there will be.

So looking back at our question, what I would like you to do now is I would like you to pause the video, and using your counters or cubes, I would like you to group the 24 children in groups of six, and see how many rows there will be.

Then I would like you to draw your array to represent your cubes or counters.

And finally, I would like you to push yourself and to have a go at writing the division equation.

I knew that there were 24 children.

Therefore, I have selected 24 counters to represent my 24 children.

And I knew that children sit in rows of six.

And I want to know how many rows there will be all together.

So I know that my children sit in rows of six, so I'm going to make, I'm going to group my counters in a group of six.

So here, I have one, two, three, four, five, six.

I've got one group of six.

Then I'm going to make another group of six.

And I'm going to keep going until I run out of my 24 counters.

So here I've got three groups of six, and I can still, I think, make another one.

So I have made one, two, three, four groups of six.

So my equation would be 24 divided by 6, 'cause I knew how many would be in each group, and that is equal to 4.

Excellent work, so just as you saw me model, we know that there are 24 children all together.

So what we do is we first are going to group the 24 in groups of six.

I don't know how many rows there are going to be, so I'm not adding a counter to each row.

What I'm doing instead is I'm going to make all of my first group, then I'm going move on to make as many groups of six as I can until I run out of my 24 counters.

And you should have had your array, should have looked something like this, and your division equation would be 24 divided by, or grouped, into six equal groups, is equal to 4.

So I have one, two, three, four groups of six.

Two, three, four, five, six.

If you got that correct, give yourself a pat on the back.

Let's have a look at another question.

So this time it's your turn.

Let's this question together, and then you're going to represent using your cubes or counters.

Then you're going to draw your array, and finally, you're going to write your division equation.

So let's read the question together.

There are 24 children.

They sit in rows of four.

How many rows are there? Pause the video and complete the question.

Having a look at my question, I know that there are 24 children.

so I have my 24 counters ready.

And I know that they sit in rows of four.

So again, I'm going to group, I'm going to make groups of four.

So that's one row, that's one group of four.

And then I'm going to keep going until I make all of my groups, and until I run out of counters.

Now it's really important to make sure that your groups are of equal size.

I'm going to add my counters until I run out of counters.

So here I can see that I have one, let's count together, two, three, four, five, six groups, or I can make six rows by grouping the children in groups of four.

So my equation would be, tell your screen.

That's right, it would be 24 divided by 4 is equal to six.

So as you saw me model, again, we knew that there were 24 children in total, or whole, and we knew how many were going to be in each group.

So we're going to group our children in groups of four until we run out of our 24 counters.

We cannot write 4 divided by 24.

Why? Tell your screen.

That's right, because division is not commutative.

We always have to begin with the whole.

We always begin with the whole, and we work out either how many parts there are, how many groups, or how many, or how many people are in each group.

Our Quick Check question, so let's have a look at the statement in the middle of our screen.

And your job after three, two, one is to point to if you think the statement is true or if you think the statement is false.

So let's read it together.

When we are dividing by grouping, we know the number of parts.

Is it true or is it false in three, two, one, point.

Good work, it's false.

Of course it's false, because what we are trying to work out is the number of parts or the number of rows that we need.

We always begin by knowing the whole and by knowing how many people or how many items are going to be in a group, and what we're trying to work out is how many groups there are, or how many parts there are.

Really well done.

And now it's time for independent task.

I'm going to read the question out for you, and then you're going to use your counters or cubes to represent the question.

Then you're going to draw your array, and underneath it, you're going to write your division equation.

So let's read the question together.

Follow with me.

How do you think the carpet spaces should be arranged for 24 children? What is a sensible size of rows? Remember, the rows should be of equal size.

That means an equal number of children should be in each row.

So we've had a look at two different ways already.

Now there are more ways that we could arrange the 24 children, and your task is to work out all of the different, or as many different ways as you possibly can, and then we are going to review the answers together.

So do that now.

Let's have a look at your answers.

We knew that we have 24 children, and if we grouped 'em in groups of six, in six groups of equal size, then we are going to have four rows.

So 24 divided by 6 is equal to 4.

Alternatively, we could have, or make a group of 24 children in groups of four, and that would leave us with six rows.

We could group our 24 children in groups of 12.

And we'd have two groups, and we could group our 24 children in groups of two, and that would leave us with 12 groups, or 12 rows.

And you might have had, or you might have grouped your 24 children in groups of three, and that would leave you with eight rows.

And alternatively, you could group your 24 children in groups of eight, and that would leave you with three rows of children.

So you have any of those answers, well done, great work.

And as we discussed, division is not commutative, that's right.

The whole always has to be at the beginning of our equation.

Well done for all of your hard work today.

If you'd like to, please ask your parent or carer to share your work on Twitter, tagging @OakNational and hashtag #LearnwithOak.

And now it's time for you to complete your end-of-lesson quiz.

That's all from me.

Thank you for joining our lesson today.

I hope you've.