Lesson video

Hello, my name's Mrs. Hopper and I'm really looking forward to working with you in our maths lesson today.

We're going to be doing some counting, we're going to be looking at numbers, we're going to be thinking about numbers, and I hope we're going to have some fun as well.

So let's make a start.

Hello, and welcome to this lesson from our Unit on Composition of numbers 11 to 19.

In this lesson, we're going to think about using our knowledge of 10 and a bit to solve problems. So let's see what we're going to be learning about.

We've got three keywords in our lesson today.

You might know them already, but let's just practise them and then we can look out for them to help with our learning.

So I'll say the word and then you say it back.

My turn, partition, your turn.

My turn, part, your turn.

My turn, sum, your turn.

Well done! As I say, you may well know those words already, but listen out for them, they're going to help us with our learning today.

We've got two parts to our lesson today.

We're going to think about addition problems in our first part, and then we're going to think about missing number problems in the second part of our lesson.

So let's get on and think about addition problems. And we've got Sam and Lucas helping us with our work today.

So teen numbers, those numbers between 10 and 20 with the teen on the end of most of them, can be partitioned into 10 and a bit.

And this can be shown on a part-part-whole model, so let's have a look.

So our whole, we know that one part is 10 and we've got another part.

So we know that they are 10 and a bit.

So we know that one part is 10, we don't know the other part, so we don't know our whole at the moment, we don't know what our part is.

So the whole has been partitioned into 10 and a bit.

We can add the parts together to make the whole, and this can be represented as an addition equation using that plus symbol, that addition symbol.

So here we've got our part-part-whole model and we know that the parts combine to make the whole and that this total, this whole is called the sum.

So here we've got 10 is a part and one is a part, and we can add them together, 10 plus 1 is equal to 11, so our sum is 11.

So the sum is what we get when we add together the parts in our part-part-whole.

And I suppose we can say that the sum is the same as the whole.

So 10 plus 1 is equal to 11, part plus the part is equal to the sum.

So Sam and Lucas are collecting stones at the park.

How many stones do they have in total? Well, Sam says, "I have 10 stones, quite a lot there, aren't there? I'm glad she's told us how many she's got, Sam's got 10 stones, so we don't need to count those.

"I have one group of 10.

One part of our stones is 10, one part is 10." So she started the part-part-whole model.

So she's put in her part of the stones, which is 10.

And Lucas says, "I have 6 stones, I have 6 ones.

One part is 6." So we've got one part of 10 and one part of 6.

So we know that we can add to the two parts to create our sum, our total number.

So 10 plus 6 is equal to, hmm, what's 10 plus 6 equal to? Well, we have 1 ten and 6 ones.

"One 10 and 6 ones is the same as 16," says Sam.

We know that is a fact, and we don't need to count to work that out.

So Sam and Lucas collected 16 stones.

The sum is 16 and 16 can be partitioned into 10 and 6.

And we can see that in our part-part-whole model.

We've got one part is 10, one part is 6, and our sum, our whole is 16.

Now they're still in the park, Sam and Lucas are counting the birds.

How many birds have they seen in total? Gosh, there's a lot of birds there.

Sam says, "I saw five birds, that's 5 ones." So she's put her five as a part in her part-part-whole model.

And Lucas says, "I saw 10 birds, ooh.

I saw 1 group of 10," he says, and he's put his 10 as his part in the part-part-whole model.

So we now know that to find the sum we can add the parts.

5 plus 10 is equal to our sum.

Sam says, "We have 10 and a bit." Lucas says, "We have 1 ten and 5 ones, and we know that 10 and a bit, we can add them together, 1 ten and 5 ones is equal to 15." So Sam says, "We saw 15 birds in total." Sam and Lucas saw 15 birds.

The sum is 15, and 15 can be partitioned into 10 and 5, and we can see that in the part-part-whole model.

15 is our sum, our whole, and the two parts are 5 and 10.

And if we add those parts together, we get our sum, our whole, 5 plus 10 is equal to 15.

This time, Sam and Lucas are collecting sticks, they're having fun in the park today, I wonder if you've been to the park and collected things, ever, how many sticks do they have in total? Gosh, that's a lot of sticks, I'm not sure I can count those all in one, so let's hope they've done some counting for us.

Sam says, "I have 10 sticks." Lucas says, "That pile is hard to count.

Thanks for saying there are 10." So I think he's as glad as we are that we know there are 10 sticks in Sam's pile.

"I have one group of 10," she says.

And she's going to record that in the part-part-whole model.

So they want to know how many sticks they've got in total.

Lucas says, "I have seven sticks.

I have 7 ones." So Sam has one group of 10 and Lucas has 7 ones, so those are our parts.

So we know we can add the parts together to find the sum, the total number of sticks.

So 10 plus 7 is equal to, oh, Sam says, "We have 10 and a bit,: and Lucas says, "We have 1 ten and 7 ones." "17 can be partitioned into 10 and 7.

So we must have 17 sticks in total." So Sam knew that 17 could be partitioned into 1 ten and 7 ones, so she knew that when we had 1 ten and 7 ones the sum would have to be 17, so they have 17 sticks.

Sam and Lucas collected 17 sticks.

The sum is 17, and 17 can be partitioned into 10 and 7.

So 1 ten and 7 ones, 10 plus 7 is equal to 17.

Time for you to check your understanding.

Which part-part-whole model and equation matches these leaves that they've collected? So we've got three part-part-whole models in their equations and we've got a set of leaves.

So which match the leaves that Sam and Lucas collected? Pause the video, and then we'll have a look at it together.

How did you get on? What did you notice? Ah, did you notice that there was one group of 10 leaves and then another 8 leaves? So we had one part was 10, 1 ten, the other part was 8, 8 ones.

So we had 1 ten and 8 ones, which gave us our sum of 18 leaves in total, and we can see that in the part-part-whole model and in the equation.

No collections here, but can you match the part-part-whole models to the correct equation, and say the sum for each? So pause the video, have a go, and then we'll look at it together.

How did you get on? Did you spot those sums in there? So the sum was 18, that's what we get when we combine 1 ten and 8 ones, our whole is 18, our sum is 18, 10 plus 8 is equal to 18.

In this one, the sum was 16.

So 10 plus 6 is equal to 16.

16 can be partitioned into 1 ten 10 and 6 ones.

So finally, these ones must match, mustn't they? Our sum is 14.

14 can be partitioned into 1 ten and 4 ones, 10 plus 4 is equal to 14.

Time for you to do some practise.

Use the pictures to show a group of 10 and fill in the missing sum in the part-part-whole model and in the equation.

So in A, it says, "Sam collected some stones.

She collected 10 stones and then 4 more.

How many did she collect?" "And Lucas collected 10 leaves and Sam collected 8 leaves.

How many leaves do they have? So have a think about those problems, complete the part-part-whole models and the equations.

And then this time, you're going to draw a picture to represent each problem and find the missing sum.

So Lucas found 3 stones and then he found 10 more, how many stones did he find in total? So you're going to draw a picture to show us and complete the part-part-whole model and the equation.

And then Lucas collected 10 leaves and Sam collected 9 leaves.

How many leaves do they have? And then you're going to finish these pictures to show a teen number.

And we know there are 10 straws.

How many more could there be? Can you find three different ways? So this time we've only given you the 10, we don't know the other part, so we don't know the sum or the whole.

So can you complete those in different ways? Pause the video, have a go, and then we'll look at them together.

How did you get on? Did you find the group of 10 in each one? So in A, Sam collected some stones, she collected 10 stones and then 4 more.

So 10 and 4 more, 1 ten and 4 ones, 4 plus 10 is equal to 14, and 14 we know can be partitioned into 1 ten and 4 ones, so there were 14 stones that Sam collected.

Lucas and Sam had both been collecting leaves, and then we've got a ring around the 10 leaves that Lucas collected, and then 8 more leaves that Sam collected.

So our parts are 10 and 8, 1 ten and 8 ones, and we know that 1 ten and 8 ones is equal to 18, so our sum is 18.

They collected 18 leaves altogether.

How did you get on with drawing the pictures to match the problems? Did you draw 10 and put a ring around them and then three more? So we know that there was one group of 10 stones and three more stones.

So 1 ten and 3 ones and 10 plus 3 is equal to 13, so the sum was 13.

And then with the leaves, Lucas collected 10 and Sam collected 9 more.

So did you draw Lucas's leaves and put a ring around them, and then 9 more for Sam? So we had 1 ten and 9 ones, and we know that 10 plus 9 is equal to 19, 1 ten and 9 ones is equal to 19, so our sum is 19.

There were different ways you might have done this.

We knew we had one bundle of 10 straws, but how many more straws could we have to make a teen number? So in our examples here, we've got 1 ten and 5 ones giving us a sum of 15.

We've got 1 ten and 7 ones giving us a sum of 17, but we've got them the other way around, haven't we? And then we've got 1 ten and 1 one, giving us a sum of 11, and we've completed the part-part-whole models and the equations to show that.

I hope you had fun with that.

I wonder what numbers you came up with.

So time for the second part of our lesson.

This time, we're gonna be looking at missing number problems. So we know that teen numbers can be partitioned into 10 and a bit.

And this can be shown on a part-part-whole model.

So we have our whole, which we don't know yet because we've got a missing part, haven't we? But we know that one part is 10 and we can partition into 10 and a bit, but we may not always be able to see the parts.

And there we've got a part covered up by a splodge.

If we know the whole and one part, we can work out the missing part.

So the whole is hmm, and one part is, hmm, so the other part must be, hmm.

So that's the stem sentence we're going to use to help us to explain our thinking.

And we're going to use our knowledge of numbers made from 10 and a bit, those teen numbers to help us.

So Sam has 15 pencils.

she's hidden some.

How many pencils has she hidden? So what can we see? She says, "We have one packet of ten." So we know that one part is 10 and we know that the sum of the pencils, all the pencils is 15.

"We know the whole is 15 and 10 is a part." So we know that 15 must be equal to 10 plus, hmm, 10 plus something.

Lucas says, "We know that 15 can be partitioned into 10 and 5.

5 are hidden because 15 is equal to 10 and 5." Let's have a look.

He's right, 5 pencils were hidden.

Let's see if we can complete our stem sentence.

Hmm, is the sum, hmm, is a part, and hmm, is a part.

So what was our sum? That's right, 15 is the sum, 10 is a part and 5 is a part.

Oh, now they've got some straws.

Sam and Lucas have 18 straws.

Some are hidden.

How many straws are hidden? So we know that the whole is 18.

We need to work out what our parts are.

Let's have a think.

Well, Sam says, "If we count our straws there, we have 8 ones.

So we know that one part is 8 ones and we know that our whole is 18.

So we know that the whole is 18 and 8 is a part." So we've got something, plus 8 is equal to 18.

Lucas says, "We know 18 is 10 and 8 'cause we've been thinking about our teen numbers in 10 and a bit.

So we know that 18 is 10 and 8.

There must be 1 bundle of 10 hidden." So 10 plus 8 is equal to 18, and there we are, there was the missing part, was our hidden bundle of 10 straws.

So let's complete our stem sentence.

What was our sum? Our sum was the same as our whole, so it was 18.

So 18 is the sum, 10 is a part, and 8 is a part.

Right, Sam and Lucas have some pencils.

So we know that the total, the sum of the pencils is 12.

We know that Sam has 10 pencils and we can see Sam's 10 pencils, we can't see Lucas's pencils.

So Sam says, "I have one package of 10 pencils.

Your part is hiding," she says to Lucas.

That's right, isn't it? And so she's filled in the part that she knows, So one part is 10 and she knows that 10 plus, hmm, is equal to 12.

Lucas says, "I have some extra pencils." Hmm, but I wonder how many? "We have 10 and a bit," says Sam, and Lucas says, "Well, 10 and 2 make 12." So if we've got 1 ten and 2 ones, we've got 12 altogether, we know that.

So Lucas thinks that our missing part is going to be 2 because 10 plus 2 is equal to 12, let's have a look.

He's right, Lucas had 2 pencils, So 10 plus 2 is equal to 12.

Time for you to check your understanding.

Lucas has 17 pencils.

He hides some.

How many are hidden? So we know that our sum, our whole is 17, and we can see that one part is a pack of 10 pencils.

So can you complete the part-part-whole model and the equation? Pause the video, have a go, and then we'll look at it together.

How did you get on? Lucas says, "I have a packet of 10 and some more." Ah, it was 7 more because 10 plus 7 is equal to 17.

17 can be partitioned into 1 ten and 7 ones, and there are the seven pencils that were hidden.

But we can partition our missing numbers into more than two parts.

So let's have a look at the straws we've got here.

Sam says, "I can see a 10 and some ones.

I have 10 straws and 2 more straws," Sam says.

So she's going to record her 10 straws and 2 more straws.

Lucas says, "I have 1 straw." So there's Lucas's 1 straw.

"Our parts are 10 and 2 and 1.

And 13 can be partitioned into 10 and 2 and 1." So we've got our 1 ten and then we can think about our 2 and our 1 together, and 2 and 1 together make 3 2 plus 1 is equal to 3.

So we've still got our 10 and a bit for 13, 10 and 3 ones, but our 3 ones have been partitioned into 2 ones and 1 one.

And Lucas says, "So this is the same as 10 plus 3." Let's have a look at this one, what can we see here? Ooh, can you see a 10 this time? I'm not sure I can.

Sam says, "I can see two groups of five and some ones." Lucas says, "We have 5 and 5 and 4," and you can see two packs of 5 pencils and 4 other pencils.

5 and 5 and 4.

Sam says, "I can see 10! 5 and 5 make 10." 5 plus 5 is equal to 10, so we have got our 10 and a bit, but this time, our 10 was hiding a bit because it had been partitioned into 2 fives.

Lucas says, "This is the same as 10 and 4 and we know that 10, 1 ten and 4 ones is equal to 14." So let's have a look at what we've got here, what can we see? Sam says, "I have 6 straws and 2 more." So she's going to record her 6 straws and 2 more.

And Lucas says, "I have 4 straws." So he's going to record his part of 4.

They know they've got 12 in total, 12 is the sum.

12 is equal to 6 plus 2 plus 4.

Can you see the 10 and a bit yet? Sam says, "I can see 10, 6 and 4 make 10.

6 plus 4 is equal to 10." And there they are, and they are equal to 10.

So Lucas says, "So this is the same as 10 and 2," and we know that 1 ten and 2 ones is equal to 12.

Time to check your understanding.

Sam has 16 straws.

How many are hidden? Say the parts and the sum, and see if you can complete the part-part-whole model and the equation.

Think carefully about what you can see and what must be hidden.

Pause the video, have a go, and then we'll talk about it together.

How did you get on? Sam says, "I have a bundle of 10 and some more." Ah, so she had 10 and 3 that we could see, but we knew it was 16.

So we've got one part is 10, and then we know that 3 plus 3 is equal to 6.

And if we've got 1 ten and 6 ones, we must have 16 in total.

Time for you to do some practise.

You're going to draw some more pencils to make the totals and fill in the missing parts for these equations and part-part-whole models.

So in part A, you can see we've got a sum of 12 and we know that one part is 10.

And in Part B, we've got a sum of 19 and one part is 9.

So can you draw more pencils to make the pictures match the part-part-whole models and the equations? And how could you check? So you've got four examples to have a go at there with the pencils.

And for the second part, you're going to use the part-part-whole models to partition these teen numbers into more than two parts.

You're going to use 10 as a part each time, but then you're going to think about how you could make the other parts to keep your sum or your whole as it is in the part-part-whole model.

So see how creative you can be, can you do this in different ways, I wonder? So for the final part, you're going to fill in the missing parts for these equations and then match the ones that have the same total.

So pause the video now, have a go at your tasks, and then we'll talk through the answers together.

How did you get on? Did you realise in, A, that we needed two more pencils to make our sum of 12? In B, We needed that group of 10, we have the 9 pencils, we needed a group of 10 pencils to make 19.

In Part C, we needed the 5 extra pencils to give us a total of 15, a whole of 15.

And in part D, we were missing our one 10, weren't we? We had our 7 and we knew to make 17, we needed 7 ones, but we needed 1 ten as well.

I wonder how you checked, did you count to check or did you use your knowledge of 10 and a bit to help you? How did you get on? You might have tried these numbers as your parts, and Lucas is going to remind us that, "If 10 is a part, then the other parts will make up the ones of our teen number." So we had to have a number that totaled 3, so we had 2 and 1 to equal the 3 of 13.

3 and 2 for the missing 5 in 15.

5 and 2 for the missing 7 in 17.

5 and 4 for the missing 9 in 19.

Are there other ways it can be done? Oh, there are, you might have tried something different.

So again, if 10 is a part, the other part will make the ones.

Well, we can have 1 and 2, we can have them in a different order, but we might have had 4 plus 1 to equal the 5 for 15,` or 4 plus 3 for the 7 for 17, or 6 plus 3 for the 9 for 19.

I wonder if you might, even have found different ways of doing it.

So finally, did you fill in the missing parts and match the equations correctly? So 10 plus 7 was equal to 17, 10 plus 2 is equal to 12, 10 plus 6 is equal to 16, 10 plus 5 is equal to 15.

2 plus 5 plus 5 is equal to 12 'cause we know that 5 plus 5 will give us our one 10.

4 plus 10 plus 2 is equal to 16 'cause 4 plus 2 gives us our missing 6.

10 plus 3 plus 4 is equal to 17.

3 plus 4 is equal to 7, and 2 plus 3 plus 10 is equal to 15 'cause 2 plus 3 is equal to 5.

Did we match the equations that have the same sum? So there we go, we can see the ones that had 17, 12, 16, and 15.

And we've come to the end of our lesson about using knowledge of 10 and a bit to solve problems. We've learned that teen numbers can be partitioned into 10 and a bit.

Problems can be represented as part-part-whole models, tens frames and equations to show the sum or the whole, and 10 and a bit can be represented in the problem.

So we saw problems where there were 10 pencils and some more, 10 straws and some more.

Thank you for your hard work today using your knowledge of 10 and a bit, and I hope to see you again sometime soon, bye-bye!.