Lesson video

Hello, my name's Mrs. Hopper, and I'm really excited that we're going to be learning together in our maths lesson today.

Hello, and welcome to today's lesson.

Today, we're all about working out what the missing number is, so we're going to use different ways of finding out what the missing number is.

And at the end of the lesson you'll be able to work out missing numbers and describe them in different ways.

We've got some key words to think about in our lesson today.

We're going to be thinking about one more than and one less than to help us find missing numbers.

And we're also going to be using the word compare and the word order to think about numbers and how we can find out which numbers are missing.

So let's have a go at saying those words.

I'll have my turn and then it'll be your turn.

So my turn.

One more than.

Your turn.

Excellent.

My turn.

One less than.

Your turn.

Well done.

My turn.

Compare.

Your turn.

Well done.

And finally my turn.

Order.

Your turn.

Excellent.

Let's look out for those key words as we go through our lesson today.

So there are two parts to our lesson today.

In the first part, we're going to be finding the missing number by counting.

And then in the second part, we'll be finding our missing numbers by comparing and ordering.

Okay, so let's get into the first part of our lesson.

And today we've got Sofia, Jun, and Alex who will be helping us in our lesson.

Alright, so Sofia is practising her counting.

So can you check that she's counted correctly? Let's count with her and see.

One, two, four, five, six, seven, eight, nine, 10.

Was that correct do you think? Jun doesn't think so? Jun says, "You've missed out the number three in your count." Should we look again? Let's just count Sofia's numbers again and have a look.

One, two, four, five, six, seven, eight, nine, 10.

Yes, there's definitely something not right quite early on in her counting, isn't there? Let's see if Jun's right and she's missed out the number three.

They're gonna count together.

So let's count together and really shout when we get to three.

Are you ready? One, two, three, four, five, six, seven, eight, nine, 10.

I wonder if you shouted louder than I did? So yes, Sofia had missed out the number three when she was counting, but by counting, we could help work out what was missing because we recognised the pattern and we could see when it had gone wrong.

This time Jun's practising counting.

He's counting backwards.

How can we check that he's counted correctly? Do you think we could count with him to see if he's got his numbers correct in counting backwards? Let's count together and see if Jun's correct.

Are you ready? 10, nine, eight, six, five, four, three, two, one.

Do you think Jun's correct in his counting? Let's see and use the number track to help us.

So let's count backwards.

Are you ready? 10, nine, eight, seven, six, five.

Oh, seven.

That was the one he'd missed, wasn't it? He says he's missed out the number seven.

So by counting, we could work out which number Jun had missed.

They're gonna practise.

So let's count backwards from 10, and let's really shout when we get to the number seven.

Are you ready? 10, nine, eight, seven, six, five, four, three, two, one.

Excellent.

I hope you didn't shout too loudly.

So something for you to check.

So all three of the children have done some counting, Jun, Alex, and Sofia, so who has counted correctly? Pause the video and have a go, and then we'll look at them together.

Did you get that right? It was only Sofia who counted correctly back from 10 to one this time.

Both Jun and Alex made mistakes.

So which numbers did Jun and Alex miss out? They've done their counting, haven't they? Can you see which number did Jun miss out? That's right, he missed out the number five.

So let's count up to 10 and shout the number five for Jun.

One, two, three, four, five, six, seven, eight, nine, 10.

And what about Alex? Which number did Alex miss out? That's right, Alex says, "I missed out nine." So let's count backwards from 10 and really shout the nine.

10, nine, eight, seven, six, five, four, three, two, one.

For Sofia, she got her numbers right the first time.

She didn't miss any numbers out.

Now it's your turn for some practise.

You're going to need some number cards from one to 10.

And if you've got a partner to play with, that will be great as well.

So what you're gonna do is pick one card from the set of cards, and that's the number you're going to miss out.

So you're going to count forwards to 10 and miss out that number, and you're gonna ask your partner to work out which number is missing.

And when you've had a go going forwards, then you can do the same thing but counting backwards.

I think Alex and Jun are going to demonstrate this task for us.

Let's have a look.

So here's Alex's counting.

So this is how he's counted.

He's counted one, two, three, four, five, seven, eight, nine, 10.

And he says, "Which number did I pick? Which number card did I pick?" And Jun says, 'cause he listened really carefully, he said, "I think you picked the number six." So if we look at Alex's counting again.

One, two, three, four, five, seven.

Ah yes, he did.

He missed out the number six.

So Alex must have picked the number six.

So have a go at that activity.

First of all, pick missing out a number counting forwards and then have another go and see if you can miss out a number counting backwards.

Can your partner work out which number card you picked up? Pause the video and have a go.

So Alex demonstrated the forwards counting when we were learning what our task was all about.

Now Jun's going to give us an example going backwards, and did Alex get it right with the number card that was missing? So Jun's gonna count backwards.

Are you ready? 10, nine, eight, seven, six, five, three, two, one.

Which number card did Jun pick? Alex says, "I think you picked number four." Do you think he's right? Let's count once more and see.

10, nine, eight, seven, six, five, three, five, four.

Yes, he missed out the number four, didn't he? So he must have picked the number four.

I wonder which cards you picked and did your partner manage to guess them? Right, so we've explored finding the missing number by counting.

Now we're going to think about using ordering and comparing to work out what number might be missing.

So let's have a look.

So we can order numbers in order to find a missing number.

We've got some cards on the screen here, but looking around, gosh, I can't tell which number might be missing.

You know, I could guess perhaps, but I wouldn't be absolutely sure.

We're going to learn about how to put the numbers in order so that we can find the missing one.

So Sofia's got a job to do.

She's got to sort out some number cards, and she thinks that there's one missing.

So she's going to put them in order to help her find the missing number.

Let's have a look.

So she's put the number cards in order so we can now see our counting in these number cards.

We can see the way that we count our numbers.

So can we count now and see if we can find if there is one missing? Let's count.

One, two, three, five, six, seven, eight, nine, 10.

That didn't sound quite right, did it? Let's count properly and compare our counting to Sofia's number cards.

Are you ready? Let's go.

One, two, three, four, five, six, seven, eight, nine, 10.

Did you spot it? Yeah, the number four is missing, isn't it? We can't see it in the cards, and when we counted, that was the number we said that we didn't see in the cards.

So by putting the cards in order, we can count more easily and find out which one's missing.

And there is our missing number four.

So here are some more cards.

So she's gonna put them in order and then we'll be able to find out more easily if there's one missing.

Okay, so here are the cards.

Sofia's put the cards in order to see if there is one missing.

So count with me and let's see.

So count and then keep an eye on those cards.

What do we notice? One, two, three, four, five, six.

Six, is the number six card there? Seven, eight, nine, 10.

No, it was that number six card that was missing, wasn't it? There we go.

So by putting the cards in order and then using our counting, we can show that the number six card is the one that's missing.

But we have to get the numbers in the right order first to make sure that we can find those missing ones.

Okay, so here are some more cards.

Are they in the right order to count? Pause the video and have a see what you think.

What did you reckon? Are those cards in the right order? One, nine, four, five.

That doesn't sound like the way we count, does it? They're not in the right order.

Let's put them in the right order.

Oh, that looks better.

So now they're in the right order to count.

One, two, four, five, six, seven, eight, nine, and 10.

Are they all there though? Which number card is missing? That's right, it was the number three, wasn't it? They said one, two, four, five, which doesn't sound right, does it? One, two, three, four, five.

So the cards are now in the right order, and the three is missing from the cards.

Now the other thing we're going to learn about in this part of our lesson is how we can compare numbers to find a missing number.

So let's have a look.

We can use more than and less than to describe a number.

So even if a number isn't there, we might be able to see that it's one more than something or one less than something.

So we can compare the numbers to see if we can work out which one is missing.

So let's have a look at these bead strings.

There's clearly a bead string missing, isn't there? There's a gap, but I wonder what number it is, and can we work it out by describing it as being one more than something and one less than something.

Let's have a look.

So we're going to say that the bead string missing is one more than hmm.

And the bead string missing is one less than hmm.

Now, those numbers probably aren't the same, are they? 'Cause if it's one more than something, that number's going to be the number before.

And if it's one less than something, the number it's less than is gonna be that one number after, isn't it? So let's have a look at the pattern we can see and see if we can work out what those missing numbers are.

So I can see numbers one, two, three, and four, but then there's a gap, so that next one's missing, isn't it? So I think we can say that the bead stringing missing is one more than four.

So then let's look at the other side of the gap because we're now going to sort of count backwards.

So we can see 10, nine, eight, seven, six, hmm, and then the missing one.

So the missing bead string is one less than six.

So we can describe our missing bead string as being one more than four and one less than six.

So what number is one more than four? And what number is one less than six? Which bead stringing is missing? The bead stringing missing is five, isn't it? Because five is one more than four, and five is one less than six.

So by working out the one more and the one less, we can help to work out which number is missing.

Let's have a look at another one.

So what can you see here? Again, we've got our bead string set, but again, we've got one missing, hmm.

So I wonder if we can think about comparing the numbers to find out which one's missing.

So which bead string is missing this time? Let's have a look.

I can see one, two, three, four, five, six, and seven bead strings there.

Hmm, but I can't find the one that is one more than hmm.

And I can count backwards 10, nine, but I can't see the bead string that is one less than a number.

So what are those missing numbers? Okay, let's have a think.

The missing bead string is one more than seven.

When we counted, we could see bead strings one, two, three, four, five, six, and seven, but we can't see the next one.

So the bead string that's missing must be one more than seven.

Let's look from the other way.

We've got 10, nine, and then one missing, so the bead string missing must be one less than nine.

So what number is one more than seven and one less than nine? Which bead string is missing? The bead stringing missing is eight because eight is one more than seven and one less than nine.

And there it is.

And we can see it's got one more bead than seven, and it's one less than nine.

It's got one fewer beads there.

So we can use comparing to work out the missing number.

So can you describe which number is missing from this number track? There's a gap there, isn't there? So which number is missing from this number track? Let's have a think.

So the missing number is, and we're gonna use that idea of one more than and one less than.

Let's have a think.

The missing number is one more than two.

We can see one, two, and then we can't see the next number.

What about one less than? So we're going to think about counting backwards this time.

So the missing number is one less than four.

That number before four is missing.

So our missing number is one more than two and one less than four.

And Alex says, "Well, the missing number's three then." Okay, so can we describe which number is missing from this number track? You can count to help find the missing number, but we're going to use those ideas of one more than and one less than to describe the number that's missing.

So let's see.

Let's count up.

We can see one, two, three, four, five, six, seven, eight, hmm.

So the missing number must be one more than eight.

If we count backwards, 10, oh, and there's our missing number.

So our missing number is one less than 10.

So what number is one more than eight and one less than 10? Alex again is there to help us.

Did you get it? Yes.

The missing number is nine because nine is one more than eight and nine is one less than 10.

Time for you to have a go.

Now, Sofia is describing one of these number tracks.

Now, there's no gap this time, so you've got to have a real look at these numbers.

Sofia says, "The missing number is one more than seven.

The missing number is one more than seven." So which number track is Sofia describing? Is it a, or is it b? Pause the video and have a think, and then we'll have a look at it together.

How did you get on? Did you work out that Sofia was describing number track b? It was the number that was one more than seven, and eight is missing, and eight is one more than seven, so Sofia was describing number track b.

Time for you to have a practise.

This is a game, again, that'd be really good if you had a partner to play with.

So what you're gonna do is take the card, so you've got your one to 10 cards there.

You're going to take your cards, but you're gonna leave one of them on the table and then you're going to order your cards.

You don't need a partner for this at all.

I'll start this.

Time for you to have some practise now.

Again, you're gonna need your number cards, your one to 10 number cards, and you're going to put them upside down on the table so you can't see the numbers.

Then you're going to take some cards, but you're going to leave one on the table.

So leave one the wrong way up on the table so you can't see that number.

And you're gonna take all the other number cards.

And then like Sofia did in her activity earlier in the lesson, she turned the cards over and then she put them in order to find out which one was missing.

So can you order your cards and find out which one you've left upside down on the table? And when you've had one go, put the cards back upside down, mix them all around, and have another go.

Take them all, but leave one on the table.

Order them and work out which number is missing.

When you've had a go at that activity, then you're going to have a look at some images, which are going to come up on the next slide.

And you're going to describe the missing number in each image to a friend.

And you're going to describe it using the idea that the number is one more than and the number is one less than.

So you're going to describe that number to a friend filling in the gaps in the sentences.

And these are the pictures you're going to be looking at.

So pause the video, have a go at these activities, and then we'll come back and talk about them together.

How did you get on? I had a go.

I took my cards and I left one of them on the table face down so I couldn't see what the number was.

So I ordered them, and then I wanted to find out which one was missing.

So can you help me? Did I get it right? Let's count these numbers and see which one is missing.

So my number cards are one, two, three, four, five, seven, eight, and nine.

Something didn't sound quite right there.

Which one was missing on the table? One, two, three, four, five, six.

Six.

Oh, I've missed out six.

So I think it was six.

Should we have a look? Yes.

The missing card was six.

I wonder if six was one of your missing cards? I hope you enjoyed playing that game.

So then let's have a look at the ordering and comparing to find those missing numbers.

So this was a, and did you work out that the missing number was five? Because five is one more than four, and five is one less than six, so that was where the missing number was.

So the missing number in a was five.

How did you get on with b? In b, the missing number was seven.

One, two, three, four, five, six, eight, nine.

That's not right.

Six, seven, eight, nine.

The missing number was one more than six and one less than eight, and seven is one more than six and one less than eight.

So in c, our missing number was three.

Three is one more than two, and three is one less than four.

And if we count, we can see one, two, four, five.

That's not right, is it? One, two, three, four, five.

But we can describe that missing number as being one more than two and one less than four.

And finally d, and our missing number was four.

And we could describe that missing number by saying that four is one more than three, and four is one less than five.

So I hope you discovered all those missing numbers and were able to describe them using more than and less than to put them in the right place in the number count.

Wow, what fantastic work you've been doing today finding missing numbers.

I hope you've enjoyed it as much as I have.

So I hope now that you can use counting forwards and backwards to find missing numbers.

But you can also order numbers and then count them to find the missing number, but also when you are looking at some numbers, that you can compare them and use that idea of one more and one less to find and describe your missing numbers.

Thank you very much for all your hard work today, and I hope to see you again.