Lesson video

Hello, my name's 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 skip counting using the group size to find the number of groups and we're going to be exploring some different scenarios, maybe taking a trip to the seaside.

That will be fun, won't it? If you're ready to start, let's get going.

There are two keywords in our lesson today.

The first one is division and then multiple.

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, multiple.

Your turn.

Well done.

I hope they're words that you've heard before, but they're going to be really useful to us in our lesson.

So listen out for them and make sure you use them when you are talking about the maths that you are doing.

There are two parts to our lesson today.

In the first part we're going to be skip counting in twos, fives, and 10s.

And in the second part we're going to use skip counting to solve problems. So let's make a start on part one.

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

Aisha and Jun skip count to solve grouping problems. Aisha says we are completing division equations.

Let's start with 16 divided by two.

So what does 16 divided by two mean? Aisha says this is the division symbol, it means splitting into equal parts.

Jun says we need to work out how many groups of two are equal to 16.

16 divided into groups of two.

So 16, this is our whole and two is the group size.

So we're taking 16 and dividing it into groups of two.

And the bit we don't know yet is the number of groups we're going to make.

As Jun says, "That's what we're trying to work out, the number of groups." Aisha and Jun use skip counting to calculate 16 divided into groups of two.

We are good at counting in twos, aren't we? So that will help us to find out how many groups of two we count.

So let's use the number rods to help work out 16 divided into groups of two.

The red number rod can help us here because we can give it a value of two.

"We'll count in twos and stop at 16," says Jun.

Two, four, six, eight, 10, 12, 14, 16.

Good counting.

How many number rods have we used though? Ah, Jun's counted up 16 divided by two is equal to eight.

We've used eight number rods to get from zero all the way up to 16 counting in twos.

So 16 divided into groups of two is equal to eight groups.

Aisha says, "We can also count forwards in multiples of two using the number line." Let's have a go.

"We have to count the number of steps we make though," says Jun.

So let's keep track of the number of steps we make.

Two, four, six, eight, 10, 12, 14, 16.

We've made one, two, three, four, five, six, seven, eight jumps.

Jun says, "We made eight steps of two.

We can count the steps on the number line." Aisha says, "That was a good way to check we have the correct number of groups." Aisha and Jun are going to use skip counting to calculate 35 divided by five.

Aisha says, "We need to work out how many groups of five are equal to 35." So let's just think about our equation.

35 represents the whole, this is the number we're starting with and five represents the group size.

We are dividing 35 into groups of five and the missing bit is the number of groups and as Jun says, "We are trying to work out the number of groups." Oh gosh, we've got a number line here going all the way up to 40.

We need to find out how many groups of five there are.

Aisha says, "Let's use the number rods to work out the number of groups." Jun says, "We'll count in fives and we'll stop at 35." So the yellow number rod can help us here.

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

How many rods did we use? It was seven, wasn't it? So Jun says, "35 divided by five is equal to 7." 35 divided into groups of five, we've got seven groups.

They're going to skip count using a number line now.

Aisha says we can also count forwards in multiples of five using a number line.

Let's count with them.

Oh Jun says though, "We have to count the number of steps we make." So let's keep track, you might be able to do that with your fingers, but if you are using a number line, we can count the jumps that we make.

So you ready to count? Five, 10, 15, 20, 25, 30, 35.

Can you count the number of jumps we made? Ha, Aisha says, "We've got the same number of groups again." And Jun says, "Yes, we made seven steps of five along our number line." So 35 divided into groups of five is equal to seven.

Aisha, and Jun used skip counting to calculate 70 divided by 10.

Can you remember what that division symbol means? Divided into groups of? So Aisha says, "We need to work out how many groups of 10 are equal to 70." 70 is our whole and we are dividing it into groups of 10.

So 10 is the group size and our unknown is the number of groups.

And as Jun says, "We're trying to work out the number of groups." Aisha and Jun are going to use skip counting to calculate 70 divided by 10.

And Aisha says, "Let's use the number rods to work out the number of groups.

Can you remember which number rod helped us with? 10? It was the orange one wasn't it? So are you ready to count? We're going to count in 10s, but we're going to keep track of how many 10s we've counted by looking at the rods.

And Jun says, "We'll count in 10s and stop at 70." 10, 20, 30, 40, 50, 60, 70.

How many rods did we use? Jun spotted it.

70 divided by 10 is equal to seven.

70 divided into groups of 10 is equal to seven groups.

Aisha and Jun skip count using the number line, but Aisha says we can also count backwards in multiples of 10 using a number line.

Jun says, "We can start on 70 and count back to zero." Are you ready? 60, 50, 40, 30, 20, 10, zero.

We made seven steps of 10 again, just like we did with the number rods.

So 70 divided into groups of 10 is equal to seven and we can count forwards or backwards in steps of 10 to check that our answer is correct.

"That's fantastic," says Aisha.

We checked our work and got the same number of groups.

Time to check your understanding now.

Can you use skip counting to calculate 25 divided by five? Remember what those numbers mean and what the division symbol means.

You could make steps in multiples of five forwards or backwards on the number line or you could use the number rods to help you if you've got them to hand.

Pause the video, have a go.

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

How did you get on? Did you count forwards or backwards or did you use the number rods to help you? Aisha says, "I'm going to skip count backwards in groups of five on a number line." So where's she going to start? She's gonna start at 25.

Should we count backwards with her? 20, 15, 10, five, zero.

How many jumps did she make? Ah, Jun says, "There were five." 25 divided by five is equal to five.

25 divided into groups of five gives us five groups of five.

Time for you to do some practise now.

Can you calculate the number of groups? We've got eight questions there.

Eight equations, all with a missing number of groups.

We know the whole, we know the group size.

Aisha says, "You could count forwards or backwards in multiples of two, five, or 10.

And Jun says, "You could use the number rods to help you to work out the number of groups." If you've got some to hand but hopefully you've got a number line to help you as well.

Pause the video, work out the number of groups and when you are ready for the answers and some feedback, press play.

How did you get on? Here are the answers.

So in A, we had 12 divided into groups of two.

How many groups was that? It was six, wasn't it? Aisha says, "I used number rods to help me work out 12 divided by two." And here they are, one, two, three, four, five, six red rods.

12 divided into groups of two is equal to six.

In B, 20 divided by five is equal to four.

So if we skip counting fives up to 20, how many do we count? Are you ready? Five, 10, 15, 20 four groups of five.

So 20 divided into five gives us four groups.

In C, we had 50 divided into groups of 10 And Jun says, "I counted backwards on a number line to work out 50 divided by 10." So let's have a look at what he did.

He started on 50 and he counted backwards.

40, 30, 20, 10, zero.

Five groups of 10.

50 divided into groups of 10 is equal to five.

And D, 14 divided into groups of two.

Well, if we skip counting twos up to 14, we will count seven groups of two.

So our missing number, our number of groups was seven.

For E, we had 45 divided by five is equal to nine.

And Aisha says, "I counted backwards on a number line to work out 45 divided by five." That's her number line.

Should we count backwards with her? 40, 35, 30, 25, 20, 15, 10, five, zero.

Nine jumps of five.

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

In F, we had 80 divided by 10.

80 divided into groups of 10.

So we could skip count forwards or backwards or use the number rods, but however we did it we'd find out that there were eight groups of 10.

In G, we had 20 divided by two.

Jun says, "I used number rods to help me work out 20 divided into groups of two." So here's our number line and what colour number rods was he using, do you think? It was the little red ones, wasn't it? One, two, three, four, five, six, seven, eight, nine, 10 number rods, 10 groups of two.

So 20 divided into groups of two gives us 10.

And finally 50 divided into groups of five.

Well if we skip counted all the way up to 50 and fives, we'd have counted 10 groups of five.

And on into the second part of our lesson.

We're going to use skip counting to solve problems. Aisha and Jun went on a school visit to a beach.

Lucky them, I do love going to the beach.

Do you like it? I wonder if you've had the chance to go to the beach.

Jun says, "We saw lots of gulls, starfish, and crabs." He says, "Gulls have two legs.

Starfish have five arms." They do, although they're sometimes called legs.

and they're often called sea stars because they're not really a type of fish.

And crabs have 10 legs including two that end with pincers.

Jun saw some gulls.

He says, "I counted the gulls legs." There were eight legs altogether.

How many gulls did I see? Aisha says I need to calculate.

Eight divided into groups of two, eight divided by two.

She says I'll count up in multiples of two using a number line.

So here's her number line.

Are you ready to count with her? Two, four, six, eight.

And each of those jumps was one gull, a pair of legs.

Eight divided into groups of two is equal to four.

Four gulls have eight legs.

So Jun saw four gulls.

Jun also saw some seastars.

He says, "I counted the number of legs." There were 30 legs altogether.

How many seastars did I see? Aisha says, "I need to calculate 30 divided into groups of five." There were 30 legs and each seastar has five legs.

So we need to know how many groups of five there were.

She says I'll count up in multiples of five using a number line.

Should we help her count? Are you ready? Five, 10, 15, 20, 25, 30.

How many seastars did Jun see? Well she says 30 divided into groups of five is six.

There were six groups of five.

Six seastars have 30 legs.

So Jun saw six seastars.

Lucky Jun.

He says, I also saw some crabs.

He's had a very busy day spotting animals, hasn't he at the seaside? He says, "I counted 50 legs.

How many crabs did I see?" Aisha says, 'I need to calculate 50 divided into groups of 10." She says, "I'll count up in multiples of 10 on a number line." Let's count with her.

Are you ready? 10, 20, 30, 40, 50.

Each of those jumps of 10 represented one crab with its 10 legs.

50 divided into groups of 10 is equal to five.

Five crabs have 50 legs.

So Jun saw five crabs.

Time to check your understanding.

He saw some gulls.

I think he saw some more gulls as well.

He says I counted six legs.

How many gulls did I see? And Aisha says, "What division calculation will help us to answer Jun?" So what division calculation are you going to find out to help? And how could you use the number line? Pause the video, have a go.

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

How did you get on? Did you spot that you needed to calculate six divided into groups of two? There were six legs and we know that gulls have two legs each.

So we needed to divide the six legs into groups of two.

And we can skip count on the number line.

Two, four, six.

So six divided into groups of two is equal to three.

Six divided by two is equal to three.

He says, "I saw three gulls." Aisha counted 10 legs.

She says, "I saw one type of creature.

How many of each creature might I have seen?" Ooh, that's interesting.

We only know about the legs.

We don't know what sort of creature she saw, but we know that they saw gulls, seastars, and crabs.

Jun says, I'm going to work out how many gulls Aisha might have seen.

He says, "I need to calculate 10 divided by two." 10 divided into groups of two.

Because we know that each gull has two legs.

He's going to use his number line to skip count.

Two, four, six, eight, 10.

10 divided into groups of two is equal to five.

10 divided by two is five.

So Aisha might have seen five gulls.

We don't actually know which animal it was she saw.

She just saw 10 legs.

So it could have been five gulls that she saw.

Over to you to check your understanding.

She says, "She saw one type of creature and she saw 10 legs." But how many of each creature might she have seen? Jun's worked out the number of gulls.

He says, 'Can you work out how many crabs or seastars Aisha might have seen?" And Aisha says, "Write a division equation to work out the number of creatures." And you might want to use a number line to help you with your skip counting.

So pause the video, work out how many seastars or crabs Aisha might have seen.

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

How did you get on? Well to work out the number of seastars, Aisha says, "You would calculate 10 divided into groups of five, 10 divided by five.

Five, 10.

That's two jumps of five, if we skip count on the number line.

10 divided into groups of five is equal to two.

So two seastars have 10 legs.

So Aisha could have seen two seastars.

To work out the number of crabs you would've had to calculate 10 divided into groups of 10 because crabs have 10 legs.

So 10 divided into groups of 10.

Skip counting 10.

We're there already.

10 divided into groups of 10 is one group of 10, isn't it? And one crab has 10 legs.

So Aisha might have seen two seastars or one crab.

I hope you work those out.

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

You are going to work out the number of animals.

Aisha says Jun saw some gulls.

He counted 12 legs.

How many gulls did he see? And you're going to write the division equation and then complete the sentence Jun saw hmm gulls.

In B, he also saw some seastars.

He counted 25 legs.

How many seastars did he see? And again, you're going to write the equation and then you're going to complete the sentence, Jun saw hmm seastars.

You could use skip counting to help you work out the answer.

And you're going to write a division equation to show the number of creatures.

And you've got some more.

He saw some gulls and he counted 18 legs.

How many gulls did he see? He saw some crabs and he counted 60 legs.

He saw some more seastars and counted 35 legs and he saw some more crabs and counted a hundred legs.

So can you complete the equations and fill in the number of animals that Jun saw? And in question two, Aisha counted 20 legs.

She saw one type of creature.

How many of each creature might she have seen? Can you work out how many gulls, seastars, or crabs Aisha might have seen? And Jun says, write a division equation to show the number of creatures.

So have a go at all those questions and when you're ready for some feedback, press play.

How did you get on? Here are the answers.

So Jun saw some gulls.

He counted 12 legs.

How many gulls did he see? Well 12 divided by two is equal to six.

So Jun saw six gulls.

And you might have skipped counted on the number line to do that.

Jun saw six gulls.

Six gulls have 12 legs.

For B, he saw some seastars and he counted 25 legs.

How many seastars did he see? Well 25 divided into groups of five gives five groups.

So Jun saw five seastars.

For C, he saw some gulls and he counted 18 legs.

How many gulls did he see? 18 divided by two is equal to nine.

18 divided into groups of two gives us nine groups, nine pairs of legs so Jun saw nine gulls.

He also saw some crabs and counted 60 legs.

How many crabs did he see? So we had to do 60 divided into groups of 10, 60 divided by 10.

And that equals six.

Jun saw six crabs.

For E, he saw some more seastars.

He counted 35 legs.

How many seastars did he see? Did you skip counting fives maybe up to 35? If you did, you counted seven groups of five.

So Jun saw seven seastars.

And in F, Jun saw some crabs.

He counted 100 legs.

How many crabs did he see? Well, did you skip count in tens? Oh, you might have gone forwards or backwards.

Whichever way you went.

You'd have counted 10 groups of 10.

So Jun saw 10 crabs.

Well done if you got all of those right.

And for two, remember Aisha saw 20 legs.

So what might she have seen? Well, if she saw gulls, we'd have done 20 divided into groups of two and we could have skipped counted in twos and we'd have counted 10 groups of two.

So Aisha might have seen 10 gulls.

And there they are, skip counting on our number line.

10 gulls have 20 legs.

So Aisha might have seen 10 gulls.

20 divided into groups of five for the seastars.

If we skip counting fives, five, 10, 15, 20, we skip count four groups of five.

So Aisha might have seen four seastars.

And if it was crabs she saw, then we had to do 20 divided into groups of 10.

And if we skip count in 10s, 10, 20, that's two groups of 10.

So Aisha might have seen two crabs.

I hope you had fun working out how many different creatures Aisha could have seen just from the number of legs.

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

We've been skip counting using the group size to find the number of groups.

We've learned that division means splitting into equal parts or groups.

Skip counting in the group size can be used to calculate the number of equal groups in a division story.

We say 50 divided into groups of 10 is equal to five.

And we can write it as 50 divided by 10 is equal to five.

And we can solve it by skip counting in 10s, 10, 20, 30, 40, 50.

That's five groups of 10.

Our whole of 50 divided into groups of 10 gives us five groups.

Thank you for all your hard work and your mathematical thinking today and I hope I get to work with you again soon.

Bye-Bye.