Lesson video

Hello, my name's Mrs. Cornwell, and I'm going to be helping you with your learning today.

I'm really looking forward to today's lesson.

I know you're going to work really hard and we'll do really well so let's get started.

Okay, so welcome to today's lesson, which is called Find the Missing Part in Addition and Subtraction Stories, and it comes from the unit: Additive Structures Addition and Subtraction.

So in today's lesson, we're going to find the missing part in both addition and subtraction stories, and we're going to be able to use some of the strategies we already have to help us do that.

Okay, so by the end of today's lesson, you should feel much more confident with finding those missing numbers in stories and equations.

Okay, so let's get started then.

So our keywords for today are, add, my turn, add, your turn, and subtract, my turn, subtract, your turn, well done! So the first part of our story today is where we're going to be finding the missing sum in an edition story.

In this lesson, you will meet Aisha and you will also meet Alex, okay? They're going to be helping us with our learning in our lesson today.

Aisha tells a 'First, then, now' addition story, but she hides the end of the story.

Collect some pennies, and act out the story to find out how many pennies there are at the end.

And Aisha is reminding us, "We can tell the story to help us, can't we?" So let's have a look.

First, there were three pennies in the piggy bank.

Then, I put three more pennies in the piggy bank.

How many pennies are in the piggy bank now? And we can represent the story with this equation, can't we? 3 plus 3 is equal to, hmm.

At the start of the story, there were three pennies, to see the number of pennies at the end of the story, I must start with three and add three more.

And we can see 3 plus 3 is equal to 6, isn't it? Well done if you got that.

There were six pennies at the end of the story.

So let's use the picture to tell a different edition story.

First, there were three counters on the tens frame, then four counters were added, how many counters are on the tens frame now? Now let's write the equation.

At the start of the story, there were three counters on the tens frame.

Then we added four counters.

So it will be 3 plus 4, those are the addends, aren't they? So 3 plus 4 is equal to, and then we don't know what the sum is, do we? So that's the missing part that we need to find.

Let's draw how many objects there were at the end of the story.

We know 3 plus 4 is equal to 7.

So there must have been seven counters at the end of the story.

So now it is time to check your understanding again.

Use counters to represent this story, tell the story, and draw the missing part, and write the equation, okay? So pause the video now while you try that.

Okay, and now let's see how you got on.

So we have to tell the story first, don't we? First, there were six counters on the tens frame, then three counters were added.

How many counters are on the tens frame now? And the equation will be 6 plus 3 is equal to, and then we don't know that missing part, the sum yet, do we? And there we go, did you get it? So 6 plus 3 more is equal to 9, excellent if you did that.

Alex wants to represent the correct equation to represent the story, let's help him.

Okay, so let's have a look at the picture here to help us, and we've got two different equations.

We've got 2 plus 4 equals mm, or 4 plus 2 equals mm.

Okay, so let's have a look.

There were four counters at the start of the story and we added two counters.

So it must be 4 plus 2 is equal to mm, that's right, because we know in a "First, then, now" story, the amount at the start of the story is the number that is written first in the equation, isn't it? So well done.

And we can see 4 plus 2 is equal to 6.

Okay, so now it's time to check your understanding again, find the correct equation to represent the story, then solve it.

So use the pictures to help you, okay? And pause the video now while you try that.

Okay, and let's see how we got on.

So, what did you think? Did you get it? So it would be B, wouldn't it? 4 plus 3, because we can see four counters at the start of the story, and then three were added.

And when you have 4 and you add 3, it is equal to 7, so well done! Okay, and then you can see that we've drawn seven counters on that tens frame at the end there, haven't we? So well done if you did that.

Okay, so Aisha and Alex add some counters to the amount of the start of this edition story, okay? So Alex says, "I added four counters," and Aisha says, "I added two counters." Alex thinks he will have more at the end of his story.

Is he right, do you think? What do we think? That's right, Alex is right.

The more that is added to an amount, the greater it becomes, and let's have a look.

So we can see he started with four, they both started with four, but then there's Aisha's, two counts added, and that takes you to six, doesn't it, as the whole amount? But then you can see Alex's four counts takes you to eight as the whole amount, doesn't it? So Alex did have more at the end,, so well done if you noticed that.

So it's time to check your understanding again, which of the following numbers if added to the start of this story, would give the greatest amount at the end? Okay, so there's the story.

remember, tell it to help you, and then you've got three options there.

A is 2, B is 1, and C is 4.

So pause the video now while you try that.

Okay, so let's see how you got on.

So we had three options at the bottom there, didn't we? And which one did you think? That's right, it was four, four is a larger number, it's a greater amount, isn't it? So if you added that to the number at the start of the story, no matter what that number at the start was, it would give a greater amount, wouldn't it? So well done if you got that.

The more that is added to an amount, the greater it becomes.

Okay, so here's a task for the first part of today's lesson.

Find the missing part in each story and equation.

So you can tell the story to help you remember, and then draw the missing part in the story, okay? And then write the correct numeral in the equation, all right? And have a look and see if you can spot any patterns, you're going to be a pattern spotter again, aren't you? So see if you can spot any patterns in the equations and then see if you can explain why they happen.

So pause the video now while you try that.

Okay, so here's the second part of your task.

Work with a partner.

And Alex is telling us, "We will each draw our own addition story with the last part missing and write the equation." And then Aisha's saying, "Then we will swap our stories and use a tens frame to solve them." Okay, so can you tell some stories that begin with the same amount and make the number at the end of the story greater each time? So have a think about what you'll have to do to do that.

Okay, so pause the video now while you have a try.

Okay, so let's see how you got on with the first part of your task.

So we had, first, we had three cakes on the plate, then we added one more cake, so now there will be four cakes on the plate.

3 plus 1 is equal to 4.

And then we can see the next one, we had three footballs and we added two more, so there were five footballs, 3 plus 2 is equal to 5, and then we can see the eggs there, can't we? And we can see we started, first we had three eggs, then we added three more, so now we would have six eggs, wouldn't we? 3 plus 3 is equal to 6, so well done if you did that.

So did you spot the pattern in that, then? So if we have a look, you can see 3 plus 1 was 4, and then when we added 2 it was 5, and when we added 3, it was 6.

So in each equation, the amount added increases by 1.

So the amount at the end also has to increase by one, doesn't it? 'Cause you put one more on, so well done if you spotted that? Okay, so now let's have a look at the second part of your task, you may have done this, and Alex is telling us what he did.

"I started my story with 5 counters and added 2 to the start," there they are.

5 plus 2 is equal to, and we need to find that missing part, the missing sum in the equation, don't we? And then Aisha says, "I knew 5 plus 2 is equal to 7, so there must be 7 counters altogether." And there is the seven counters.

"Then, to make the amount greater, I added more counters." So we know that if we add more counters, then the amount at the end of the story will be greater, won't it? So well done if you spotted that.

Okay, so now it's time for the second part of our lesson where we will find the missing difference in a subtraction story.

Alex thinks he has solved this "First, then, now' problem before.

But Aisha's saying, "This is different to our other missing part stories.

This time it is a subtraction story.

Some pennies were taken out of the piggy bank." Act out the story to find out how many pennies there are at the end of the story.

First, there were six pennies in the piggy bank.

Then I took three pennies out of the piggy bank.

How many pennies are in the piggy bank now? So at the start of the story, we know where there were 6 pennies, don't we? I know that 6 is the whole amount at the start, and 3 is the part subtracted.

So the other part must be 3, that's right.

3 pennies were taken out, so we must subtract 3, 6 minus 3 is equal to mm, that we know that with the 3 pennies at the end of the story, when 6 is the whole and 3 is a part, the other part must be 3.

Okay so let's use the picture to tell this subtraction story, okay? First there were 7 counters on the tens frame.

Then 4 counters were subtracted.

How many counters are on the tens frame now? Let's write the equation.

At the start of the story, there were 7 counters, then we subtracted 4 counters.

7 minus 4 is equal to, hmm.

And we're trying to find the difference in the equation, that's the big part that's missing this time, isn't it? Let's draw how many objects there were at the end of the story.

We know that 7 is the whole amount and 4 is the part subtracted, so the missing part must be 3.

There are 3 counters left on the tens frame.

7 minus 4 is equal to 3.

Okay, so now it's time to check your understanding again.

Use counters to help you tell the story.

Draw the missing part and write the equation, okay? So pause the video now while you try that.

Okay, and let's see how you got on.

So, let's tell the story.

First, there were 9 counters on the tens frame, then 2 counters were subtracted.

How many counters are on the tens frame now? And then the equation will be 9 minus 2 is equal to, mm.

So what did you think? That's right, 7, 9 minus 2 is equal to 7.

So, Alex wants to find the correct equation to represent the story, okay? So we can see the story here, and there are two equations to choose from.

There is 1 minus 7 is equal to, mm, or 7 minus 1 is equal to, mm.

So we need to tell the story to help us.

Okay, So let's see what Alex thinks.

He says, "I think that this can be represented as 1 minus 7 is equal to mm." And Aisha's saying that, "That can't be right." How does Aisha know? That's right, there were seven counters at the start of the story, so the equation must start with seven.

7 minus 1 is equal to 6.

So that was a correct equation, wasn't it? Well done! So now it's time to check your understanding again, find the correct equation to represent the story, then solve it, okay? So you can see the story there and you can tell it to help you, and there are three options, there's A, 2 minus 6 is equal to mm, B, 2 minus 4 is equal to mm, and C, 6 minus 2 is equal to mm, so pause a video now while you have a think about that.

Okay, and then let's see, how did you do? There were 6 counters at the start of the story so the equation will start with 6, okay? So 6 minus 2 is equal to hmm.

And we know that if 6 is the whole and 2 is apart, the remaining part must be 4, so well done if you got that.

And there they are, we've drawn them.

Aisha and Alex are playing a game where they subtract some counters from the amount at the start of this story.

Alex says, "I will subtract 3 counters," and Aisha says, I will subtract 4 counters." The winner is the person with the smallest amount at the end of the story.

Who will win the game? Explain how you know, what do we think about that? Okay, who will have the smallest amount? That's right, Aisha will win.

The more that is subtracted from an amount, the smaller it becomes.

And there we could see, that if she subtracted 4 counters from the 4 at the start, she would have no counters left, would she? So now it's time to check your understanding again, which of these numbers, if subtracted from the amount at the start of this story, would lead the smallest amount at the end? Okay, and so you've got three options there.

You've got 2, 1, or 4, okay? So which one of those if subtracted, would leave the smallest amount? So pause the video now while you think about that.

Okay, and let's see, what did you think? That's right, it's four, isn't it? Four is the largest amount there.

So if you subtract four, then it would leave a smaller amount.

The more that is subtracted from an amount, the smaller it becomes.

So well done, excellent! And there we can see the four that were left, can't we? So well done if you've got that.

So now it's time for the task for the second part of our lesson.

Complete the missing part in each story and equation, okay? So remember you can tell the story to help you, okay? And draw the missing part in the story and then write the numeral in the equation.

And then we're going to be pattern spotters again.

So let's have a look and see if you can see any patterns and if you can explain why those patterns are happening.

And then the second part of your task is here, work with a partner.

Alex is telling us what we have to do.

"We will each draw our own subtraction story with the last part missing and write the equation." "And then we will swap our story," says Aisha, "and use a tense frame to solve them." Can you tell some stories that begin with the same amount and make the number at the end of the story smaller each time? I wonder what you would have to do to do that.

So pause your video while you have a try at that.

Okay, so let's see how we got on with the first part of our task, then.

So here we are, we've got some cakes on a plate, haven't we? So first, there were six cakes on a plate, then one cake was subtracted, so now there are five cakes on the plate.

6 minus 1 is equal to 5.

And then let's look at the next story.

First, there were six balls in the box, then two balls were subtracted, now there are four balls in the box.

6 minus 2 is equal to 4.

And then finally, first there were six eggs in the egg box, then three eggs were subtracted, so now there are three eggs left.

So 6 minus 3 is equal to 3.

And did you spot any patterns in that? If we have a look, 6 minus 1, 6 minus 2, and 6 minus 3, so we're taking away one more each time, aren't we? And so, what happens to the missing part? In each equation, one more is subtracted, so the amount at the end of each story decreases by one, doesn't it? So well done if you spotted that.

So let's see what you did in the second part of the task, then.

So Alex is saying, "I started my story with 10 counters and subtracted 2," and you can see his counters there on the tens frame, he's shown what he's done, hasn't he? And then Aisha's found out that the remaining part must have been eight.

So the equation will be 10 minus 2 is equal to mm, and we know it is 8.

"I knew 10 minus 2 is equal to 8, so there must be 8 counters left." To make the amount at the end smaller each time, I subtracted more counters in each story I told, because we know that the more that you subtract, the smaller the amount of counters will get.

So well done if you did that.

So excellent, you've worked really hard and now hopefully, you are feeling much more confident with finding the missing sum in addition stories and the missing difference in subtraction stories.

So excellent work! So let's have a look and see what we learned in today's lesson, then.

So we found out the more that is added to an amount at the start of a 'First, then, now' story, the greater the amount at the end of the story will be.

And the more that is subtracted from the amount at the start of the story, the smaller the amount at the end of the story will be.

So well done, excellent work.

I've really enjoyed working with you today!.