Lesson video

Hello, my name is Mrs. Hopper, and I'm really looking forward to working with you in this lesson.

The lesson comes from our unit, "Introduction to division structures." So we're going to be looking at how we can divide numbers up.

Are you ready to make a start? If you are, let's get going.

So in this lesson, we're going to be calculating the number of equal groups in a division story.

You might have been exploring equal groups and maybe even starting to use a symbol to represent division.

And this time, we're going to look at the number of equal groups that we make in a division story.

We've got two keywords in our lesson.

We've got division and equation.

So I'll take my turn to say them and then it'll be your turn.

Are you ready? My turn, division.

Your turn.

My turn, equation.

Your turn.

Excellent.

They may be words that are a little bit new, but listen out for them and we'll think about what they mean as we go through our lesson today.

There are two parts to our lesson.

In the first part, we're going to be using a division equation.

And in the second part, we're going to be using skip counting to calculate the number of equal groups in a division story.

So if you're ready, let's make a start on part one.

And we've got Aisha and Jun helping us with our learning today.

Jun's mum owns a bakery, lucky Jun.

He says, "We help her to work out how many bags and boxes she needs for the cakes and cookies." Aisha says, "Cookies go into bags in pairs," so in twos.

"And cakes go into boxes of five or 10." So there we can see cookies in pairs.

We can see some cakes in a box of five and we can see cakes in a box of 10.

I think those are Jun's favourite, the chocolate cakes.

There are 12 cookies.

Two cookies go into each bag, and we can write that as 12 divided into groups of two.

This time we've got an equal sign, so we're going to find out how many groups there are and record the full equation.

So we've made one group of two.

Two, three, four, five, six groups of two cookies.

Six pairs of cookies.

So, Aisha says, "We need six bags." 12 divided into groups of two is equal to six.

So 12 was the number of cookies we had to start with.

Two is the size of the groups we were putting them into.

And six is the number of groups we made, the number of bags we need.

"And we can use a bar model to represent this," says Jun.

There are six groups of two cookies.

So 12 has been divided into groups of two and there are six of those groups.

Let's have a look at these cakes, there are 20 cakes here.

And Jun says, "Five cakes go into each box." So we can write that as 20 divided into groups of five.

How many groups of five are there going to be? One, two, three, four.

All the cakes have been put into boxes, five in each box.

And Aisha says, "We need four boxes." 20 divided into groups of five is equal to four.

20 was the whole number of cakes we started with.

We divided into groups of five, five cakes in each box, and our answer was four.

That was the number of boxes we needed, the number of groups we've made.

And Jun says, "We can use a bar model to represent this.

There are four groups of five cakes." 20 has been divided into groups of five, and there are four equal groups of five.

There are 30 cakes here, the chocolate ones, Jun.

10 cakes go into each box.

So we can write that as 30 divided into groups of 10.

And there it is, using our division symbol.

One, two, three boxes of 10 cakes.

Aisha says, "We need three boxes." 30 divided into groups of 10 is equal to three.

30 was the whole number of cakes we started with, divided into groups of 10.

That's how many cakes are in each box.

And three represents the number of groups we made and the number of boxes we need.

And Jun says again, "We can use a bar model to represent this.

There are three groups of 10 cakes." 30 divided into groups of 10 is equal to three.

Time to check your understanding now.

There are 14 cookies, two cookies go into each bag.

Did you count how many bags there were? Find the missing number to complete the division equation.

14 divided into groups of two is equal to.

Hmm.

14 divided by two is equal to.

Hmm.

And Aisha says, "How would you represent this using a bar model?" Pause the video, have a think about completing the sentence, completing the equation, and what the bar model would look like.

And when you're ready for some answers and feedback, press play.

How did you get on? Seven bags are needed.

You could have counted them, couldn't you? 14 divided into groups of two is equal to seven.

14 divided by two is equal to seven.

14 was the whole number of cookies we started with.

We divided them into groups of two, so the two represents how many are in each group, and we made seven equal groups.

We needed seven bags.

And there's our bar model.

14 divided into groups of two gives seven equal groups of two.

Now there are 25 cakes.

Five cakes go into each box, how many boxes are needed? Jun says, "I'm going to solve the problem and complete the equation." He's got one box, two boxes, three boxes, four boxes, and five boxes.

"We need five boxes," said Aisha.

25 divided into groups of five is equal to five.

There's a lot of fives going on there.

Let's see what they all mean.

25 divided into groups of five is equal to five.

So 25 was the whole number of cakes that we started with.

We divided them into groups of five, five in each box, and we needed five of those boxes for all of the cakes.

And the bar model shows five groups of five cakes.

So we've got five equal parts and five in each part this time.

Time to check your understanding.

There are 10 cakes, five cakes need to go into each box, how many boxes are needed? "Solve the problem and complete the equation," says Jun.

And you could represent the problem using a bar model.

You might be able to use the cakes there to help you as well.

So complete the stem sentences and complete the division equation.

Pause the video, have a go, and when you're ready for some answers and feedback, press play.

How did you get on? Did you realise that we could make one, two groups of five cakes out of our 10 cakes? So 10 divided into groups of five is equal to two, and we can record that as a division equation.

10 was the whole number of cakes we started with, five was the size of the group, 10 divided into groups of five, and two was the number of groups we made or the number of boxes we needed.

So there are two groups of five cakes, and there it is represented as a bar model.

10 is our whole and there are two groups of five cakes.

Time for you to do some practise now.

You are going to complete each problem.

Work out how many bags or boxes are needed.

So A says there are 10 cookies, two cookies go into each bag.

So you're going to complete the stem sentence and the equation, and the bar model.

And you could represent the problem using counters or cubes.

We've just got 10 cookies this time.

And then can you complete B and C? This time we've got 15 cakes, and five cakes go into each box in B.

And in C, 20 cakes, and 10 cakes go into each box.

And for question two, again, complete each problem, work out how many bags or boxes are needed.

So in A, there are eight cookies, and two cookies go into each bag.

In B, there are 30 cakes, and five cakes go into each box.

Pause the video, have a go at those problems, and when you're ready for some answers and feedback, press play.

How did you get on? So for A, we had 10 cookies, and two cookies go into each bag.

So we had 10 divided into groups of two and it's equal to five.

10 divided by two is equal to five, and our bar model shows 10 divided into equal groups of two, and there are five of those groups.

So 10 in our equation represented the number of cookies, two represented the number of cookies in each group, and five represented the number of groups or the number of bags we needed.

So we needed five bags.

And as Aisha says, "We need five bags with two cookies in each bag." For B, there were 15 cakes, and there were five cakes going into each box.

So 15 divided into groups of five is equal to three.

We can fill three boxes.

So Aisha says, "We need three boxes with five cakes in each box." Our equation represents 15, which was the whole number of cakes, divided into groups of five, so five represents the size of the group.

And it's equal to three.

Three is the number of groups we made, the number of boxes we need.

And we can see that in the bar model as well.

And in C, there were 20 cakes, and 10 cakes go into each box.

So 20 divided into groups of 10 is equal to two.

We can fill two boxes.

20 is the whole number of cakes, divided by 10, divided into groups of 10.

So each group had 10 cakes in it, and we could make two groups so we needed two boxes, and we can see that in the bar model.

And Aisha says, "We need two boxes with 10 cakes in each box." For question two, we had eight divided into groups of two was equal to four.

And we can see that in the cookies in the bags in the bar model, and we can represent it as an equation.

Eight is the whole number of cookies, divided into groups of two.

Two represents the number of cookies in each group and four represents the number of groups we made or the number of bags we needed.

We need four bags.

And B said 30 was divided into groups of five.

And we could make six groups of five.

30 divided into groups of five is equal to six.

We can see that in the bar model.

So 30 in the equation represents the number of cakes to start with, our whole, divided into groups of five.

So five represents how many cakes were in each group.

And we could make six groups.

So we need six boxes.

And on into part two of our lesson.

This time we're going to use skip counting to help us with our division.

There are 40 cakes, five cakes go into each box, how many boxes are needed? Jun says, "That's a lot of cakes.

I think we're going to need lots of boxes." Aisha says, "We could use skip counting." We know that there are five cakes in each box, don't we? I wonder what we could skip count in.

Ah, Aisha says, "We could count in fives and stop when we reach 40." So here's the number line marked in fives.

So we're going to count five at a time.

Are you ready? Five, 10, 15, 20, 25, 30, 35, 40.

Great counting, but how many did we count? Well, Jun says, "There are eight groups of five cakes." So each time we counted, there was one group of five cakes, and we counted eight times to get to 40.

So we need eight boxes, he says.

And Aisha says, "40 divided into groups of five is equal to eight." 40 was the whole number we had.

We divided into groups of five, five in each group, and we made eight groups.

And we can represent that with our division equation.

40 divided into groups of five is equal to eight.

Jun says, "Could we count backwards too using skip counting?" Aisha says, "We could.

We'd start at 40 and count back in fives until we reach zero." Shall we help them out? Are you ready? So we start on 40, 35, 30, 25, 20, 15, 10, 5, 0.

And we could use times table facts too, says Jun.

We counted back eight groups of five as well, didn't we? He says, "I know that eight times five is equal to 40." So if I have 40 cakes and I've got to put them into groups of five, I know from my times tables that there'll be eight groups.

40 divided into groups of five is equal to eight.

40 divided by five is equal to eight.

And that's how we would record it as a division equation.

So we've got lots of strategies we can use there.

We could count up in fives, we could count back in fives, or we could use our five times table facts to help us.

What about this one then? There are 16 cookies, two cookies go into each bag.

How many bags are needed? We've got another number line here.

Can you think how skip counting might help us? Jun says, "Let's use skip counting.

We need to count in twos from zero to 16." Two, four, six, eight, 10, 12, 14, 16.

How many twos did we count? Jun says, "There are eight groups of two cookies." We need eight bags to put the cookies in.

16 divided into groups of two is equal to eight.

And can you think how that would look as our division equation? That's right.

16 represents the whole number of cookies, divided into groups of two.

So the two represents the size of each group, and that's equal to eight.

Eight was the number of groups we could make or the number of bags we would need to put all the cookies into bags.

Time to check your understanding.

There are 35 cakes.

Five cakes go into each box.

How many boxes are needed? Jun says, "Let's use skip counting to work out how many boxes are needed." Are you ready to count? Five, 10, 15, 20, 25, 30, 35.

So what is 35 divided into groups of five? Pause the video, have a think, and when you're ready for the answer and some feedback, press play.

How did you get on? Did you spot that there were seven groups of five cakes.

We skip counted seven times to get up to 35.

Seven lots of five.

Seven boxes are needed.

35 divided into groups of five is equal to seven.

35 was the whole number of cakes.

We were dividing into groups of five, so that's what our five represents.

And it was equal to seven.

There were seven groups of five in 35, so we'd need seven boxes.

This time there are 50 cakes, 10 cakes go into each box, how many boxes are needed? "Let's use skip counting.

We need to count in tens from zero to 50," says Jun.

So there's our number line to help us.

10, 20, 30, 40, 50.

How many groups were there? There were five, weren't there? Aisha says, "50 divided into groups of 10 is equal to five." There were five groups of 10.

And we can represent that with our division equation.

50 divided into groups of 10 is equal to five.

50 represents the whole number of cakes, 10 represents the size of the group, and equal to five represents the number of groups that we made or the number of boxes we needed.

So we needed five boxes, as Jun says.

And Jun says, "Let's count backwards to check how many boxes are needed." So we're going to count backwards from 50 in tens.

Are you ready? 40, 30, 20, 10, 0.

Five jumps again.

50 divided into groups of 10 is equal to five.

50 divided by 10 is equal to five.

Time to check your understanding.

There are 40 cakes, 10 cakes go into each box, how many boxes are needed? Use skip counting to work out how many boxes are needed.

Pause the video, have a go, and when you're ready for the answer and some feedback, press play.

How did you get on? Shall we count together? 10, 20, 30, 40, we had 40 cakes this time.

"40 divided into groups of 10 is equal to four," says Aisha.

40 divided into groups of 10 is equal to four, and then we can represent that with our equation as well.

Oh, and Jun reminds us we need four boxes.

That's what we were trying to solve, wasn't it? Well done if you got that right.

Great skip counting.

And it's time for you to do some practise.

So for question one, you're thinking about cookies and remembering that two cookies go into each bag, and you're going to use skip counting to work out how many bags are needed for, in A, eight cookies, in B, 18 cookies.

And Aisha says, "You could count forwards or backwards." And in question two, five cakes go into each box and you're going to use skip counting to work out how many boxes are needed for, in A, 45 cakes, and in B, 55 cakes.

And in question three, 10 cakes go into each box.

I think those were the chocolate cakes, weren't they? Can you use skip counting to work out how many boxes are needed for, in A, 60 cakes, and in B, 80 cakes.

So use your skip counting in the number lines and write down the equations that would represent those problems to work out how many bags or boxes are needed.

Pause the video, have a go, and when you're ready for some feedback, press play.

How did you get on? So here are the answers.

For eight cookies, two, four, six, eight, so we had four jumps on our number line.

Eight divided into groups of two is equal to four.

So four bags are needed for the eight cookies.

What about B? Two, four, six, eight, 10, 12, 14, 16, 18.

18 divided into groups of two is equal to nine.

So nine bags are needed.

And what about two? This time, the cakes were going into boxes of five.

So we were counting in fives.

So for 45 cakes, 45 divided into groups of five is equal to nine.

So nine boxes are needed.

And for B, there was a lot of counting to do here.

55 divided into groups of five is equal to 11.

So 11 boxes are needed.

And in question three, we were putting the cakes into boxes of 10 each time.

So we were skip counting in tens.

So for 60 cakes, we count six times.

60 divided into groups of 10 is equal to six.

So we need six boxes.

And for 80 cakes, 80 divided into groups of 10 is equal to eight.

So we need eight boxes.

I hope you were successful in working out how many bags and boxes were needed for the cookies and cakes.

And we've come to the end of our lesson.

We've been calculating the number of equal groups in a division story.

We've learned that skip counting can be used to calculate the number of equal groups in a division story.

We say that 50 divided into groups of 10 is equal to five, and we can write it using the division symbol.

It means the same.

50 divided into groups of 10 is equal to five.

50 represents our whole, 10 represents the size of the group, and five represents the number of groups.

And we could use that to work out how many bags and boxes were needed for the cookies and the cakes in Jun's mum's bakery.

I hope you've enjoyed thinking about cakes and cookies.

I am feeling quite hungry now.

I hope it's lunchtime for you as well, maybe.

I hope I get to work with you again soon.

Bye-bye.