Lesson video

Hello there, my name is Mr. Tilstone.

Give me a thumb up if you are having a good day, give me two thumbs up if you are having a great day.

I've got two thumbs up, I'm having a great day.

Would you like to know why? It's because I get to teach you a lesson all about fractions and that's something that I really enjoy.

Maybe you are becoming quite a fractions expert.

Maybe you know lots about halves.

Maybe you know lots about quarters.

Today we're going to learn about a new fraction.

So if you are ready, help me to count down to the lesson.

Are you ready? Five, four, three, two, one.

Let's begin.

The outcome of today's lesson is this.

I can name the fraction one-third in relation to a fraction of an object, shape, or set of objects and explain how I know it is a third.

So you know, hopefully about halves.

You know about quarters.

Let's learn about thirds.

And our keywords, if I say them, will you say them back? My turn, third.

Your turn.

And my turn, one-third.

Your turn.

Very good.

Our lesson today is split into two parts.

The first part will be third of an object and the second thirds in different contexts.

But for now, let's focus on third of an object.

Are you ready? And in today's lesson, you're going to meet Sofia and Izzy.

Have you met them before? They're here today to give us a helping hand with our maths.

Sofia and Izzy want to share this cake, this delicious looking cake between themselves and their friend.

Okay, so let's think about how many people that is.

That's Sofia, that's Izzy, and that's their friend.

How many is that? That's three people.

Izzy says there are three of us.

We need to divide the cake into three pieces.

Can you think of a way to do that so that it's fair? How would you do it? How would you cut that cake? Sofia says, "I can carefully cut it into three pieces." Let's have a look.

How about that? What do you think of that? Would you say that's fair sharing? She says, "I cut the cake fairly so that we will all get the same amount".

Yes indeed.

I would be happy to get any of those three pieces of cake.

They're all the same.

Izzy says, "The whole cake has been divided into three equal parts".

That's very important.

Three equal parts.

When the whole has been divided into three equal parts, each part is called one-third.

Have a look at this cake this time, what do you think? Is that fair sharing? Are they thirds? Are they equal parts? Izzy says, "My part is now bigger so it's not one-third?" and lucky Izzy, but she can't say she's got one-third of the cake.

And Sofia says, "My part is smaller so it's not one-third.

So they're not one-thirds." When the whole has been divided into three unequal parts, each part is not one-third.

And you can see they're unequal.

They're not the same size.

Let's practise saying Sofia's sentence to help remember what one-third means.

So I'll say it and then we'll say it together and then just you'll say it.

Are you ready? So listen to me first, when the whole has been divided into three equal parts, each part is one-third.

Okay.

Do you think we could say that together? After three.

One, two, three.

When the whole has been divided into three equal parts, each part is one-third.

Very good, now just you please.

Off you go.

Sofia says, "Did you know that one-third is a fraction?" So just like one half is a fraction, just like one quarter is a fraction, one-third is a fraction.

"So a fraction," says Izzy, "shows that a whole has been divided into equal parts." Yes.

So when a shape has been divided into two equal parts, each part is half, one half.

When a fraction is divided into four equal parts, each part is one quarter.

And when a fraction is divided into three equal parts, each part is one-third.

So well done Izzy, that's right.

Let's do a little check.

Let's see what you've understood.

Izzy has tried to say Sofia's sentence, but she has forgotten some of the words.

Can you help Izzy to complete the sentence? So well done Izzy for remembering some of those words.

We'll help you out though, don't worry.

She's remembered this, "When the whole has been divided into Hmm hmm parts.

Each part is hmm." So she's forgotten some of the sentence.

Can you help her? Pause the video and have a go.

Let's have a look.

When the whole has been divided into three equal parts, each part is one-third and we can see that with the cake.

Izzy and Sofia share some more food.

It's a rectangular slice of pizza.

They are checking if each part is one-third or not.

Let's have a look.

What do you think? Is each part one-third? Izzy says, "What happens if one of the slices of pizza is a tiny bit smaller? Are the parts still equal?" And Sofia says, "When you divide something like pizza, the parts may be very slightly different.

We can still call them equal parts because they're as equal as we can possibly make them.

And I think that's a case here.

I can see the whole has been divided into three equal parts.

That means that each part is one-third.

And I dunno about you, I would be equally happy to get any of those three slices of pizza.

Do you think each part is one-third? Let's have a look.

Would you say each part is one-third? It has been split into three parts.

Are they equal sized parts? Izzy says, "I can see the whole has been divided into three unequal parts".

They're not the same.

That means that each part is not one-third.

Let's do another one.

Let's do this watermelon.

Do you think each part's one-third? Are you ready? Let's have a look.

What do you think? Is each part one-third? What do you notice? Well, they are equal size parts, aren't they? I would be equally happy to get any of those parts.

Are they one-thirds though? Izzy says, "I've learned about this before.

Each part is one quarter." You knew that didn't you? Not one-third.

It is four equal parts, not three.

So we can't say they're one-thirds.

We can say they're one quarters.

And Sofia says, "Well, remember Izzy, the whole has been divided into four equal parts.

Making them quarters but not one-thirds." Let's have a look.

Do you think each part is one-third? We've got a bar of chocolate.

Let's see how we're going to divide this.

Is each part one-third.

Can you prove it? Izzy says, "The whole has been divided into three equal parts".

Yes.

Each part has got two segments of chocolate.

Each part is equal.

I would be happy to get any of those three pieces of chocolate.

Sofia says, "That means that each part is one-third." Let's do a little check.

Do you think each part is one-third? And how do you know? Are you ready? Should have a look.

Pause the video.

What do you think? Can we see one-thirds here? Well, there are three parts.

The three parts of the pie though are not equal.

They're unequal.

So each part is not one-third.

We cannot say these are one-thirds.

Sofia says, "I wonder how you could cut the pie so that each part is one-third." Tricky.

Have you got any ideas? What could you do? Circles are very tricky to divide into thirds.

I think it would look like this.

And before we look at Izzy's idea, I wonder if you could sketch that circle on your whiteboard and see if you can divide it into three equal size pieces.

Let's have a look what Izzy's got.

Did you do something like that? They are now three equal sized pieces.

So we can say that each part is one-third.

Sofia says, "Great work, Izzy, that does look tricky".

It is time for some practise.

I think you are ready.

Number one, tick the objects that have been split into thirds.

And I'm looking there and I can see some that do not have equal sized pieces.

And Sofia says, "Can you explain to a partner why you didn't tick some of the pictures?" Number two, complete the sentences by writing one-third or not one-third.

So look very carefully, see what you notice about each.

And then when you've done that, see if you can find any more objects around you that have been split into thirds.

Have a little hunt around your classroom.

Have fun with that.

Good luck and I'll see you soon for some feedback.

Welcome back.

Did you have fun there? Are you becoming a one-thirds expert? Let's find out.

So the objects that have been split into thirds are as follows.

Three equals size parts, three equals size parts, three equals size parts, three equal sized parts.

What about the other two? Sofia says, "I did not tick the orange because the three parts are not equal".

So it has got three parts, but they're unequal, so we can't say they're thirds.

And what about the pizza? I can see equal sized parts, but I can see four equal size parts, making those one quarters.

And complete the sentences by writing one-third or not one-third.

So for the first one I can see equal size pieces, but there are four of them, not three, making those one quarters not one-thirds.

What about the second one? Three parts And each part is one-third.

Three equal sized parts.

And what about the next one? I can see three parts, but they're unequal.

So they're not one-thirds.

And what about the final one? I can see three parts.

They're equal sized.

So each part is one-third.

And then Izzy had a little hunt around and she found a pretend pizza in the play kitchen that's divided into three equal parts, making each part one-third.

What did you find? Did you find anything interesting? Have you shared it with your class? You are doing really well.

You are well on your way to becoming a one-third expert.

So let's carry on.

Now we're going to look at thirds in different contexts.

Sofia has been practising finding thirds in lots of different ways and you can see some examples here.

She's getting really good at it.

She says, "I am an expert at recognising thirds now." Well done Sofia, very confident.

What about you? Are you an expert? And Izzy says, "That's great.

Maybe you could give me a little help." Izzy's on her way to becoming an expert but she's not quite as far along as Sofia is, she needs a little help.

Let's help her.

When the whole has been divided into three equal parts, each part is one-third.

That's our big generalisation for today.

That's a big important learning from today.

So let's have a look at this.

Izzy's had a go at dividing a rectangle into one-thirds.

Would you say she succeeded or not? What would you say to her? She wants to know, "Has this shape been split into thirds?" What would you say? Well, I would start by saying, well done Izzy, because you know that thirds relate to three pieces and I can see three pieces there, but those pieces are unequal.

So we can't say they're one-thirds.

She's had another go.

That's what good mathematicians do.

When they don't succeed, they try again and they try something different.

What about now? Is this rectangle split into thirds? Is it divided into thirds? What do you think? Izzy wants to know, "What if I split it this way?" What would you say to Izzy? Sofia says, "Yes, that's right.

Now each part is one-third." We can see three equal sized pieces.

Sometimes there is more than one way to find one-third of a shape.

So here we've got a square and it's split into three equal size pieces.

And one of them has been highlighted in green.

And here's another example, again it's split into rectangles.

They go a different way this time.

What about this one though? That's a bit different, isn't it? Each shape has been divided into three equal parts.

Each shape has one-third shaded.

Have a look at these examples.

What do you notice? Do you think these have been split into one-thirds? Izzy thinks so.

She says, "I've found three different ways to divide this shape into thirds".

We'll have a look.

What do you notice? Sofia says, "Two of these are right, but you've made one mistake".

Can you spot the mistake? I've seen it, I've noticed it.

Which one is it? One of those is not right.

Two of those are split into three equal parts and one of them is not.

It's got unequal parts.

Can you spot it? It's the bottom shape.

It's got two bigger pieces and one smaller piece.

But like the good mathematician that she is, she's going to have another go.

Has she fixed it? Yes.

Now all the shapes have been divided into three equal parts, well done Izzy.

Each part is one-third.

Let's do a little check.

Which shapes have been divided into thirds? Have a look.

I can see that each of these shapes has been divided into three parts, but are they equal? Pause the video.

Which ones were divided into thirds, into three equal sized parts? Well this one was, that circle three equals size parts, three equal sized parts.

But the other two are not split into three equal sized parts.

They are three unequal parts.

So each part is not one-third.

Sofia's been practising finding thirds in lots of different ways.

Can you see thirds here with the birds and the nests? Can you see three equal sized parts? I can.

One-third of the birds are in each nest.

The whole group of birds has been divided into three equal parts.

And now one of the birds has moved.

Would you say they're still equal parts? Are these still one-thirds? "Now one of the birds has flown to a different nest.

This does not show thirds." They're not equal parts.

Look at these yummy looking cakes.

How do these cakes show thirds? It's a little bit trickier, isn't it? What do you notice here? One-third of the cakes have a cherry.

So you could split those into three equal size groups and one of those groups have got cherries on.

What about now? What do you think? I could see six cakes and five of them have got cherries on.

Some more cherries have been added.

This does not show that one-third of the cakes have a cherry.

So that image is not showing one-thirds.

Let's have a check.

Let's see how you are getting on.

Which sweets have been divided into thirds and how do you now? So look very carefully at each picture, which one is showing thirds? Pause the video and have a go.

What do you think? These sweets do not show thirds because the whole has been divided into two equal parts.

So each part is one half, they're showing halves.

However, these sweets have been divided into three equal parts.

Each part is one-third, each part has two sweets.

I would be happy having any of those three parts.

It's time for some final practise.

You're doing really well, you're ready for this.

Number one, find the shapes that have been divided into thirds and shade one-third of each shape.

If it's not possible to shade one-third, draw across on that shape.

Number two, this part is one-third.

What could the whole look like? Draw as many different wholes as you can.

And Sofia says you could cut shapes from paper to try out your ideas.

That's a good idea.

Before you draw them.

Righty-ho, pause the video and off you go.

Welcome back, how did you get on with that? Are you feeling confident? You're doing well.

So number one, find the shapes that have been divided into thirds and shade one-third of each shape.

That one's not one-thirds, three parts but not equal parts.

This one is, and you could have shaded any of those three parts.

That's one example.

And this one is one-thirds and that's one of the parts shaded.

This shape does not have equal sized parts.

This one does, so you need to shade any of those three equal parts.

And the same with this shape.

This shape does not have equal size parts.

Two of them are bigger and one smaller.

This one does have equals sized parts.

So you can shape any of those three equal parts.

And that one does have equal size parts.

So you can shade any of those three parts.

And that one does not have equal sized parts.

And this part is one-third, what could the whole look like? Well, there are so many possibilities here.

So you might not have the ones that we're showing here.

You might have some different ones.

And Sofia cut out some paper triangles to try out her ideas before she drew them.

She used three paper triangles because she knows that one-third means a whole has been divided into three equal parts.

So her triangles were all the same size, just like this.

And that's one way that you could put them together so she could draw that.

That's a different way you could put them together so she could draw that.

That's a different way again, that she could put them together.

I like that one.

She could draw that.

The three paper triangles could be in any arrangement whatsoever.

The whole has still been divided into three equal parts.

They're all showing one-thirds.

We've come to the end of the lesson.

I've had so much fun today.

I hope you have too.

Today we've been recognising and naming the fraction one-third.

When the whole has been divided into three equal parts, each part is one-third of the whole.

You can find thirds of objects, shapes, and sets of objects.

And here are just a few examples of one-thirds.

My final question for you is this.

Are you a one-thirds expert? Give me a thumbs up if you are a one-thirds expert.

Well done.

Well, I hope I get the chance to spend another maths lesson with you in the near future 'cause this has been fun.

Until then, enjoy the rest of your day.

Try really hard, work really hard, and be successful.

Take care and goodbye.