# Lesson video

In progress...

Hello mathematicians! It's Ms. Charlton and my taught partner, Hedwig here, all ready for some more learning.

How is everybody feeling today? I'm feeling quite energised.

I'm feeling ready for this maths lesson.

How are you all feeling? Maybe you're feeling energised as well.

Maybe you're feeling a bit sleepy today and you need waking up.

Well don't worry, this maths will definitely wake you up.

Should we find out what we're going to do? We are going to use doubles to calculate near doubles.

What on earth is that? Let's find out! We're going to recap doubles, our double within 20.

Then, we're going to calculate near doubles.

So, numbers that are almost double.

You're going to need a pencil and some paper and you might need a whole part model.

You can draw that out or you can use the pictures that are on the screen to help you.

Let's get reminding ourselves of our number bonds and "If I know, then I know" strategies because we might use those words today.

So, if I know that the whole is 9 and the parts are 7 and 2, then I know.

Hmm? Do you think you could say that one? Then I know that.

have a little think.

And then, shout it at the screen! Then I know that 7+12 is equal to 19! Well done! Have a look at what's different there and what's the same.

Well I can see that they both got 7 as a part and they both got the ones unit as a 2 and the one is a 9, but the difference is we have a 10 in the second number bond, don't we? Instead of it being 7+2=9, it's 7+12=19.

Well done.

That's quite complicated, isn't it? But hopefully that's got your brains warmed up.

Now, I went shopping and I bought some batteries.

But, I was very lucky because there was a special deal on at the shop.

Have you ever been shopping before where they've had a deal on that says "buy one, get one free." Has anyone ever been? Put your hand up if you have.

What did you buy? Did you buy lots of lovely things like sweets? Well, I bought batteries.

Less exciting than sweets.

And I paid for this amount.

How many did I pay for? 1, 2, 3, 4, 5.

I paid for 5 and I got a pack free.

So, I got all of those batteries free.

How many batteries did I get all together? Hmm.

Well, I paid for 5 and if you buy one pack, then you get one free.

So I bought another five.

All together it equals 10.

So, I got 10 batteries all together, but I only paid for 5.

Oh, 5+5? That's double! Let's have a look at it on a bead's string, to be sure.

I paid for 5, I get.

? Hmm.

Let's have a look.

1, 2, 3, 4, 5.

.

1, 2, 3, 4, 5.

5+5=10.

Double 5 is equal to 10.

I paid for 5, but I got 10 all together because I got some free.

Let's try that again with these batteries.

I paid for 3 and I got 3 free.

That's doubles! I'm doubling the amount.

I pay for 3, but I get 3 free.

How many do I get all together? Pause the video now and have a think and then shout it at the screen.

How many batteries did I get all together? Have a think.

Can you shout it at the screen after 3? Ready? 1, 2, 3! That's right, I got 6 batteries all together.

I paid for 3, but I get 6.

3 batteries in one pack and 3 in the other pack.

It was a good day to go shopping, wasn't it.

So now, we're going to use that knowledge that we just recapped, that was our knowledge of doubling.

Doubling a number.

We're going to use that knowledge to help us with the next section of learning.

4+5? Hmm.

Now, is that double? No, it's not.

4+4 would be double but 4+5 isn't double.

But it's very close isn't it.

Let's look at the cubes.

I can see 4 green cubes on both of them and 1 extra red cube.

So, its nearly double but not quite.

Oh! Near doubles! That's what our learning objective said we were doing today! 4+5 is the same as saying 4+4+1.

4+5=4+4+1.

Can you say that? Really well done everybody.

So, 4+4, that's double four, and then one more.

Double four and one more.

Hmm.

So let's write that out as an equation.

4+5=? Let's see if you can figure that out.

Pause the video, use the cubes to help you count, but see if you can figure out what the equation is.

Let's check together now.

4+5=9 because 4+4, double four, is 8.

And one more is 9.

And you can double check on the cubes.

4, 5, 6, 7, 8, 9! We got there.

Did you all get there in the end? Let's check that again, with another example.

If I know 3+3=6, then I know 4+3=7 because 4+3 is a near double to 3+3.

3+3 and one more.

3+3=6, 4+3=7.

One more than 3 is 4 and one more than 6 is 7.

Now we know, from our number bonds, that if we know 4+3=7, 3+4=7.

There are so many equations! So many ways of representing the same equation.

Let's check that again quickly together.

If I know 3+3=6 then I know 4+3=7 and 3+4=7.

So let's have a little bit more of an explore.

These two children think that they fully understand this idea, but one of them has made a bit of a mistake.

Let's see if we can figure out what mistake they made.

To calculate 3+4, I can double 3 and then add 1.

She's using her knowledge of near doubles.

To calculate 3+4, I can double 4 and then add 1.

Hmm.

Who is right and who is wrong? Who has made the mistake there? Can you have a look and have a think, who might have made a mistake? The little boy made a mistake because to calculate 3+4, he's saying I can double 4 and then add 1.

So, lets do that.

We know that double 4 is equal to 8.

4+4=8.

And then, add one more is 9.

Double 4 is 8 and one more is 9.

Hmm.

So does that mean that 3+4=9? Well I can just count on to check that.

4, 5, 6 ,7.

No, it's not is it.

So, he has doubled the wrong number.

He's doubled the bigger number.

Now the little girl says, to calculate 3+4, I can double 3 and then add 1.

Should we see if we can figure that out? Let's double 3.

Double 3 is equal to? 3+3=6! And then add 1 more, it's 7! Double 3 is 6 and then add 1 more is 7.

Oh! Yes! We said, 3+4=7.

You must double the smallest number.

That's a bit tricky, isn't it.

Now it's your turn to have a go.

All you have to do is pick a number from this list below, double it, and add 1 more.

What number do you end up with? So, for example, if I took the number 2.

I double it, and add one more.

Let's see that again, Number 2, double it.

That's 2 and 2.

2+2=4.

And add 1 more, it's 5.

2+2+1=5.

You get now to have a lovely time exploring all of these numbers on the screen to double them and add 1 more.

Pause the screen now and then come back and we will check all those answers together.

Are you ready to go through them.

So the first example was 2+2+1=5.

Then, 3+3+11=7.

4+4+1=9.

5+5+1=10.

6+6+1=13.

7+7+1=15.

8+8+1=17.

9+9+1=19.

We have done so much exploring with our doubles and our near doubles.

I think before we finish and before we explain to Hedwig, we need some kind of celebration.

What shall we do? Maybe, a rainbow clap! Are you ready? I love that one! Okay, are you ready to wake up Hedwig? Wake, wake Hedwig! Wake, wake! Now, what did we do? I really enjoyed today's lesson Hedwig because we were talking all about doubles, and I got to go pretend shopping and I bought some batteries and I ended up getting free ones! Because I doubled the amount.

I bought one and I got one free! So, we practised doubling and then we used that knowledge of doubling to add near doubles.

That means, when the numbers aren't quite double, there is just a difference of one.

So, for example, instead of saying 4+4 we might know 4+5.

If we know 4+4, then we know 4+5.

It makes adding much quicker and simpler.

So we recapped the double and then we recalculated near doubles.

Do you think you'd be able to do that? Lovely maths today everybody! I had a great time exploring with you! Go and complete your quiz now and I'll see you again soon! Bye-bye!.