Lesson video

Hello, my name's Mrs. Cayley and I'm going to be your teacher for today's lesson.

We are going to be learning about conservation of number.

Don't worry if you don't know what this means yet, you'll know by the end of the lesson.

So let's see what we'll be learning today.

Here's the outcome of today's lesson.

So by the end of the lesson, you'll be able to do this.

I can explain that when a number of objects has been rearranged, that means they've moved position or they've swapped round, the amount stays the same as long as nothing has been added or taken away.

Here are our keywords for today's lesson.

You might have seen these before.

You might know what they mean already.

Let's have a look at the first one, the same.

Can you say it? The same.

This means that nothing has changed, it has stayed the same, or two amounts are the same, they are equal.

The second key word is none.

Can you say it? None.

This means there's nothing there.

There's none there.

It's empty or there's zero.

The last keyword is some.

Can you say it? Some.

This means that there are some, there's something there that we can count.

It's the opposite of none, isn't it? Well done.

This is our lesson outline for today.

So in the first part of the lesson, we will recognise when a number of objects has been rearranged.

That means they've moved round or they've swapped.

And the last part of the lesson, we will recognise when objects have been added or taken away.

And we'll think about whether the amount stays the same or whether it doesn't, whether it changes.

Let's look at the first part of the lesson.

Here are some children that we'll meet in the lesson today.

They're going to help us with our learning.

So we've got Alex, Izzy, and Jun.

Let's start with the learning.

Can you count the pieces of fruit? That's right, there are four pieces of fruit.

Count the pieces of fruit now.

Yes, there's still four pieces of fruit.

What do you notice? Did you see that some of the pieces of fruit have swapped over, they've moved? But is it still the same? Are there still four pieces of fruit? Yes, because even when objects change position, the amount of objects stays the same.

Count these pieces of fruit.

That's right, five pieces of fruit.

Count the pieces of fruit now.

Yes, it's still five pieces of fruit.

Well done.

What did you notice? Did you see that they moved apart? They're more spread out now.

But is it still the same? Are there still five pieces of fruit? Yes, because even when objects move, the amount of objects stays the same.

Count the pieces of fruit here.

There are three pieces of fruit.

Count the pieces of fruit now.

Yes, it's still three pieces of fruit.

What did you notice this time? Did you see that some of them are bigger and some are smaller? Or it looks like some are closer and some are further away.

But is it the same? Are there still three pieces of fruit? Yes, because even when objects appear different in size, perhaps because they're closer or further away, the amount of objects stays the same.

Here are some groups of straws.

Who is correct? Jun said, "I think the images show the same amount of objects." Izzy said, "I do not think they show the same amount of objects." Who do you think is right? Who is correct? That's right, it was Jun.

Did you see that there were three straws in both of the groups? And that's the same, isn't it? Even though some of them have moved in the second group, it is still the same.

The same or not the same amount? You are going to see some groups of objects.

Can you decide whether they are showing the same amount, you can put a thumbs up for the same, or not the same amount, you can put thumbs down for not the same.

So you ready? The same or not the same amount? That's right, that was showing the same.

We've got four straws in both groups.

Four is the same as four.

Even though they've moved a bit, it was still four.

The same or not the same amount? That's right, it was not the same this time.

Did you notice an extra straw in one of the groups? So we've got four straws in one group and five in the other group.

That is not the same, is it? Four is not the same as five.

The same or not the same amount? That's right, it was not the same.

Did you see that extra counter in one of the groups? So we had three counters and then we had four counters.

That's not the same, is it? The same or not the same amount? That's right, it was the same.

They are both showing three counters even though they've moved in one of the groups.

Here's a task for you to have a go at.

Can you find six counters or you can find six objects and can you arrange them in different ways? And I want you to think about, does the amount of counters change or does it stay the same? So you need to find six counters or six objects like I have.

I've put mine in a line.

And then try moving them and arranging them in different ways and ask yourself, is it still the same or has it changed? And you could draw a picture of the different ways that you arrange your counters or your objects or you could take some photos.

But ask yourself, is it still the same? Pause the video and have a go.

So we asked you to find six counters or six objects and arrange them in different ways and think about does the amount change? No, there are still six counters.

So you might have arranged them in different ways like I have, but every time it's still the same.

There are still six counters.

Well done.

Now we're onto the second part of our lesson.

We're going to recognise when objects have been added or taken away and we'll think about whether the amount is still the same or not.

Here are some cakes on a plate.

Can you see how many there are at first? That's right, there are three cakes.

Now how many cakes are there? What do you notice? Did it stay the same or did it change? Are there still three cakes on the plate? Is the amount the same? Yes, it was.

When none have been added or taken away, the amount of objects stays the same.

Now we've got some pencils in a pencil pot.

Can you see how many there are at first? There are two pencils.

Now how many pencils are there? What do you notice? Did anything change? Is the amount still the same? Yes, there are still two pencils.

When none have been added or taken away, the amount of objects stays the same.

Look at the cakes on the plate.

Look how many there are at first, then watch carefully, see what happens.

Did you notice? Now how many cakes are there? What do you notice? Did you see one more cake appear? Is the amount the same? No.

When some have been added, the amount of objects is not the same.

So we had three cakes at first and then another cake appeared, we had four now.

Three cakes is not the same as four cakes.

Look at the cakes on this plate.

How many have we got first? There are three cakes.

Then, watch carefully, see what happens.

Did you notice? Now how many cakes have we got? What do you notice? Did you see one of the cakes disappear? Somebody's eaten it.

Is the amount the same? No.

When some have been taken away, the amount of objects is not the same.

So we had three at first and now we've only got two cakes.

We've got some pencils in a pencil pot.

Can you see how many there are at first? Then, watch carefully.

Did you see what happened? What have we got now? What do you notice? Did you see one pencil appear in the pot? Is the amount the same? No.

When some have been added, the amount of objects is not the same.

So we had two pencils in the first pot and then three in the second pot.

They are not the same.

Two pencils is not the same as three pencils.

We've got some more pencils in a pencil pot.

At first we had this many pencils.

Then, watch carefully.

Did you see what happened? Now how many pencils have we got? What do you notice? Did you see one pencil disappear? Is the amount the same? No.

When some have been taken away, the amount of objects is not the same.

So we had two pencils and now we've only got one pencil.

That is not the same.

Here we've got some cakes on the plate.

Look how many there are first of all.

And now look at the cakes.

Who do you agree with? Jun thinks, "I think some have been added." Izzy said, "I think some have been taken away." Alex said, "I think the amount has stayed the same." Who do you agree with? Who do you think's right? That's right, it was Alex.

The amount did stay the same.

There were four cakes first and now there are still four cakes.

They just moved a bit on the plate, didn't they? But it is still the same amount of cakes.

Look at these cakes on the plate.

First, we've got this many.

Now we've got this many.

Who do you agree with? Jun said, "I think some have been added." Izzy said, "I think some have been taken away." Alex said, "I think the amount has stayed the same." Who do you agree with? Who do you think's right? It was Jun.

I think some have been added.

Did you see an extra cake appear on the plate? Someone put an extra cake on.

So at first we had four cakes and now we've got five cakes.

That is not the same, is it? Look at the cakes on this plate.

First, we've got this many cakes.

Now we've got this many cakes.

Who do you agree with? Jun said, "I think some have been added." Izzy said, "I think some have been taken away." Alex said, "I think the amount has stayed the same." Who do you agree with? Who do you think's right? It was Izzy this time.

I think some have been taken away.

Can you see one of the cakes has disappeared? Maybe Izzy has eaten the cake.

Who is correct this time? Izzy said, "When none have been added or taken away, the amount stays the same." Alex said, "When some have been added or taken away, the amount stays the same." Who do you agree with? Who is correct? That's right, it was Izzy.

When none have been added or taken away, the amount stays the same.

Alex thought when some have been added or taken away, the amount stays the same.

But it will change, won't it? If we add or take away some, the amount will change.

It won't stay the same.

Here's your next task.

Can you find five counters or five objects and put them on a tray or on a plate or on your table? And if you've got a partner to play this game with, can you ask your partner to close their eyes and you can add or take away some or none and then ask your partner how many counters there are now.

Is it the same or is it not the same? So here are my counters on my plate.

I've got my five counters.

And then I'm going to do something.

I'm going to add or take away some or none.

Can you see what I did? I took away some, didn't I? I took away all of them.

And can you ask your partner, is the amount the same or not? When you've tried it with five counters, you could try it with different numbers too.

So pause the video and have a go at this game with your partner.

This is your second task.

Can you match the sentences with the words same, none, or some? So here are our sentences and here are the words that we're going to match.

So the first sentence says, even when objects move, the total amount stays the _.

So you've got to pick the right word to go on that gap, same, none, or some.

The second sentence says, when _ have been added or taken away, the amount of objects is not the same.

And the third sentence says, when _ have been added or taken away, the amount of objects stays the same.

So think about which word goes on each gap, and be careful because two of these words sound very similar.

Same and some sound very similar, don't they? So be careful with those two.

So pause the video, see if you can match the right word up with the right sentence.

How did you get on with your task? Did you play the game with a partner? So you might have tried having five counters on your plate and then add or take away some or none and ask your partner, is it still the same or not? So you might have tried leaving it as it was, so taking away none.

Is it still the same? Yes.

Or you might have taken away one counter.

Is it still the same? No, not anymore, is it? You might have taken away another counter.

Is it still the same? No.

You might have taken away another one.

Is it the same? No.

You might have taken away another one.

Is it still the same? No.

You might have taken away all of the counters.

Is it still the same? No.

It's only when we add or take away none that it stays the same.

If we add or take away some, it will not be the same.

It will change.

How did you get on on the matching task? So here are our sentences and here are the words that we were matching.

So the first sentence said, even when the objects move, the total amounts stays the same.

That's right.

The second sentence says, when _ have been added or taken away, the amount of objects is not the same.

When some have been added or taken away, the amount of objects is not the same.

And the last sentence says, when _ have been added or taken away, the amount of objects stays the same.

That's none, isn't it? So we had, even when objects move, the total amount stays the same.

When some have been added or taken away, the amount of objects is not the same.

And when none have been added or taken away, the amount of objects stays the same.

Well done on that task.

So we've got to the end of the lesson and hopefully you've learned all about conservation of number now and how we can keep amounts the same.

So this is what we've learned today.

Even when objects move position, the amount stays the same.

When some have been added or taken away, the amount of objects is not the same.

When none have been added or taken away, the amount of objects stays the same.

Well done everyone, really good job and I'll see you next time.

Bye.