Lesson video

Hello, mathematicians.

It's me, Miss Charlton and Hedwig.

I just nearly dropped Hedwig on the floor.

I'm so sorry, Hedwig.

Are you cross with me? No.

Oh, she's so forgiving, isn't she? I'm ever so sorry.

You go there and be nice and safe.

Right, are you all ready to see what we're going to be learning today? Today, we are going to subtract by counting back using a number line.

We're going to use some first, then, and now stories to describe subtraction.

And then we'll show subtraction on a number line and a number track.

Then you'll do your independent task and your end of lesson quiz.

Today you're going to need a pencil and some paper.

Are you ready to start off with a brain teaser? I think I need my brain warming up a bit.

I'm a bit clumsy today, aren't I? With poor Hedwig.

Right, we've got some number bonds here and we've got some cubes in the number bonds opposite, and we need to match the number bond to the picture.

So can you have a look carefully and see if you can figure out which number bond is representing the one in the picture.

Count carefully and have a little think.

Hmm.

Shall we check together? I think that it's this one.

Because I can see that the whole is unknown at the moment, it's not filled in, and the parts are 2, there are 2 yellow cubes, and 6, there are 6 green cubes.

The whole is unknown.

The parts are 2 and 6, but we could find the whole, couldn't we? By adding 2 and 6 together, 6 plus 2, 2 plus 6 is equal to 8.

Hopefully you are nice and warmed up now and ready to start our lesson.

So let's get your hands ready.

Hands up, star words.

First, then, now.

Those are the words that we'll need in today's lesson.

We've got our first number problem here.

Our first number story.

First, there were 13 children sitting on the carpet.

Then 2 left the carpet.

How many children are there now? Ooh, they're our star words, first, then, now.

So how could we work that out? First there were 13 children, then 2 left.

If 2 children are leaving the carpet, what's happening to the number, the total, the whole? Is it getting bigger? Is it increasing or decreasing? Let's have a think.

There were 13 and then 2 children left.

So that means the numbers are decreasing.

They're getting smaller, which means we must be doing a subtraction equation.

Can everyone show me subtraction? You can do a tiny one like that.

Or you can do a big one like that.

Well done.

So let's have a look at this problem on a number line.

First there were 13 children.

I've highlighted the number 13.

Then 2 children left the carpet.

Now, if the numbers are getting smaller and decreasing, we need to move down the number track towards the number 1.

The numbers are not increasing, they are decreasing.

There's 1, 2.

2 children left the carpet.

So there are 2 jumps.

How many children are there now? What have I landed on? I've landed on the number 11.

13 take away, subtract 2 is equal to 11.

Let's have a look at that as an equation now.

The whole, we started off with 13.

The whole was 13, and then I took away 2, 2 children left.

13, subtract 2 is equal to 11.

The whole is 13.

The parts are 2 and 11.

13 subtract 2 is equal to 11.

Can you say that? Well done.

Fantastic mathematical equation.

Now it's your turn to try it.

We've got another number story here.

First, there were 12 pencils in the pot.

Then I took 3 out to draw a picture.

How many pencils are in the pot now? Hmm, let's have a think.

First of all, what operation am I doing? Am I doing addition or subtraction? I started off with 12 and then I've taken some out.

It means the numbers are getting smaller.

So we're doing, can you shout at the screen for me? Good, subtraction.

Well done.

So we're doing subtraction.

Let's have a look at that on a number track.

First there were 12.

So I've started at 12.

Then I pick out 3.

So how many jumps do I need to do if I'm taking away 3? Can you tell me? Good, 3 jumps.

Show me on your fingers, 3.

1, 2, 3.

How many pencils are in the pot now? Where have I ended up? I've ended at the number 9.

Let's go for an equation now.

What was the whole? What did we start with? 12, well done.

And I took away how many? 3.

3 pencils came out of the pot.

Which is equal to 9.

Well done.

Let's read that as a full equation together.

12 subtract 3 is equal to 9.

Fantastic mathematical language.

I think we need a celebration.

Let's do, or let's not wake Hedwig because I already almost dropped her on the floor.

Should we do a fairy clap so we don't wake her? Get your fingers ready.

Well done, really good.

Well done, mathematicians.

Now let's try it with a number line.

This time we've got eggs and someone's been doing some baking, but it looks like they've been a bit clumsy.

First I had 18 eggs.

Then I smashed 3 of them, oh no.

Do you think they went all over the floor? How many eggs are left now? So there's my story.

First, then, now.

First I had 18.

Let's have a look.

Then I smashed 3.

So how many jumps do I need to do? 3 jumps.

1, 2, 3.

How many eggs are left? There are 15 eggs left.

So as an equation, the whole would be, can you tell your talk partner? The whole is 18.

Did you tell your talk partner that as well? Good.

The whole is 18.

Subtract 3.

I dropped 3 eggs.

Is equal to 15.

There are 15 eggs left.

Let's say that as a full equation.

18 subtract 3 is equal to 15.

Brilliant job.

I think you are ready to try this by yourself.

Today you have got 4 different independent tasks with these stories.

So the first one is a tree with acorns on.

Do you think that might be where Hedwig lives? Should we wake her up and ask her? Or should we leave her to rest? Let's leave her to rest.

So we've got a tree full of acorns, but 1 acorn fell off the tree.

How many acorns are there now? So you need to count the acorns, carefully, in the picture, subtract 1 and find out how many are left.

Make sure that you do the jumps on the number line and you show it in the equation.

Once you've done that, you're going to do it again with eggs, more smashing eggs, and then pretty butterflies, and then batteries.

Once you've done that, come back and we'll check the answers together.

Don't worry if you find it tricky, we can go through them.

How did everybody get on? Now, I counted the acorns carefully and I counted 13 acorns on the tree.

And then 1 fell off.

So I had subtracted 1 and that was equal to 12.

13 subtract 1 is equal to 12.

Can you say that? Well done.

Let's try the next one.

I started off with 16 eggs and I smashed 3.

16 subtract 3 is equal to 13.

Then the butterflies.

There were 18 butterflies, then 3 of them flew away.

Did you create that as a story? And then that equaled 15.

There were 15 butterflies left.

And finally with the batteries, there were 17 batteries.

2 of them, what could we say? Did two of them break maybe? We could say two of the batteries broke.

So we started off with 17 batteries.

2 of the batteries broke and there are 15 batteries now.

You've done such a great go with your learning today, everybody.

Shall we wake Hedwig up now and tell her what we did? Come on, Hedwig.

I'm sorry that I nearly dropped you, but we did such great learning today.

And we really want to tell you what we did.

So, what did we do? Well, we used a number track and a number line to have a look at how the numbers change when we subtract, when we take away.

And we saw that the numbers were decreasing, getting smaller.

Then we use the first, then, and now stories to describe what happened, what the change was when we subtracted.

Do you understand, Hedwig? She does understand.

Really good job, everybody.

Now you can go and complete your quiz and I'll see you again very soon.

Bye bye.