Lesson video

Hello my wonderful mathematicians, it's me Ms. Charleton and Hedwig.

Oh my gosh Hedwig's head's the wrong way round.

Hedwig, turn round, there we go.

Oh Hedwig, now that you've stopped being silly hopefully we can get on with our maths lesson.

Let's see what we're learning today everybody.

So today we're going to describe and classify 2-D shapes.

We'll go through the description of the 2-D shapes, and then we'll classify them that means put them into two different groups depending on their properties.

Then you'll do your independent task, and an end of lesson quiz.

You'll need a pencil, some paper, and if you're cutting out your own shapes or drawing your own shapes you might need some scissors and a ruler.

But be very careful if you're using the scissors.

Let's start off with a brain teaser.

I really need to get my brain warmed up, I don't know about you.

So in front of you, you've got some cubes, some coloured cubes.

Now those all represent a number bond to ten.

So the first stack of cubes, they are all red.

They show ten red cubes.

And there are no yellow cubes.

So the number bond would be ten and zero, ten plus zero is equal to ten.

Then the next stack along, there are nine red cubes and one yellow cube.

The whole is still ten, but the parts there are nine and one.

Do you think you can have a look, and figure out the number bonds to the rest of the stacks of cubes then we'll check them together.

Let's have a look.

So we've got ten and zero, nine and one, eight and two, cause there are eight red cubes and two yellow cubes.

Seven and three, six and four, five and five, and then three and seven.

Do you notice how we had seven and three, and three and seven.

Then two and eight, one and nine, zero and ten.

Well done, hopefully your brains are nice and warmed up.

All ready to learn about some shapes.

Let's go through our star words to start off with.

Get your hands ready, hand up star words.

Vertex, vertices, straight, oblong.

Those are the words that we'll see if we can use in today's lesson to classify the properties of our shapes.

Let's have a recap.

Now what does a shape need to have to be a rectangle, or we might call it oblong.

What does a shape need to have to be a rectangle or oblong.

Let's have a look carefully at these shapes in front of us.

What is the same about them, and what's different.

Let's think about what's the same.

How many sides have they all got? One, two, three, four.

And the red one has got one, two, three, four.

And the blue shape has got one, two, three, four.

So they've all got that in common.

They all have four straight sides.

How many vertices do they have.

One, two, three, four.

One, two, three, four.

One, two, three, four.

All of the shapes have got four vertices or four corners.

They all have four straight sides, four vertices or four corners, and let's have a look at their sides.

Two of them are short and two of them are long.

So we say they have two sides longer than the other two.

So the properties of a rectangle or an oblong are four straight sides, four vertices, and two sides longer than the other two.

What's different about these shapes? Well they're different colours, one of them's green, one's red, one's blue.

And I can see that they are all at different angles, they're positioned differently.

So we need to move our heads to be able to spot the shapes sometimes.

The green one's quite easy to spot because it's obviously right in front of us but the red one is a bit of a tricky one.

Can everyone turn their head to the side like this, now can you see that red shape it looks more like a rectangle when you're at that angle.

So shapes sometimes try and trick us.

The properties are all the same, but they look a little bit different depending on how they're positioned.

Now let's explore a square.

We'll do the same again.

What's the same about all of these shapes, what have they got? How many sides have they all got? Can you count them? One, two, three, four.

One, two, three, four.

One, two, three, four.

All of the shapes have got four sides to them, a little bit like the rectangle, just like the rectangle in fact.

Now what about the vertices, how many corners or vertices have they all got.

One, two, three, four.

They've all got four vertices as well.

So they've got four straight sides, just like the rectangle.

They've got four vertices, just like the rectangle.

But the difference is, that their sides have all got an equal length unlike the rectangle which has two sides longer than the other two.

Now let's have a look at these shapes what's different about them.

Well the colours different.

I've got a yellow one, an orange one, and a pink one.

And just like the rectangles, can you turn your head and see that naughty yellow one on its side.

It's trying to trick us isn't it.

It's trying to disguise itself so that it doesn't look like a square.

But we know that it is because we've learned the properties of a square, so there's no tricking us.

We're fantastic mathematicians aren't we? Let's have a look now at this shape.

What does a shape need to have to be a triangle.

Well unlike the rectangle and the square, it does not have four sides.

How many sides does a triangle have? Let's count.

One, two, three, that's right a triangle has three straight sides.

It has three straight sides, and how many vertices does it have? Can you count them? One, two, three, three vertices.

Three vertices, and three straight sides.

Those are the properties of a triangle.

I think we've done really really well recognising our shapes there.

Shall we give ourselves a hulk clap.

Are you ready? Hulk! Can you do that? Hulk! Really well done.

Now I've got a bit of a trick for you.

Which of these shapes do you think are triangles.

Remember to use the knowledge that you've just learned about the properties of triangles.

Let's have a look carefully.

Which ones are triangles.

Now there are some in there that are trying to trick us, but we know that this one is a triangle because it has one, two, three, straight sides, and three vertices.

We know that this one is a triangle, and we know that this one is a triangle.

Can you see how they've all got three straight sides, and three vertices? But they're all at slightly different angles.

We just have to turn our heads, to see them carefully because they're trying to trick us.

Now what about the other ones.

What about the yellow one, and the orange one.

They look like they might be triangles because they've got three sides, haven't they? And it looks like they've got three vertices, but are the sides straight? No.

Are the sides, are the vertices all joined up, no.

So those ones are trying to trick us as well.

Which of these shapes are oblongs or rectangles? Now we know the properties of the rectangles and oblongs.

We know that they need to have four straight sides well done and four vertices, and who can tell me about the sides.

What do we know about the sides, they need to have two sides longer than the other two.

So which of those shapes are rectangles or oblongs.

We know that it's this one, and this one.

There are two other shapes there that look similar because they've got four sides, and they've got four vertices but those shapes are squares because all of the sides are of equal length.

Really great spotting of those properties everyone.

Now it's time for you to do your independent task.

Your job is to sort out these shapes.

They're all muddled up at the bottom, they're trying to trick us again, they're being very naughty.

You need to put them into the groups depending on whether it is a triangle or not a triangle.

Remember to use that knowledge that you've learned about the properties of triangles to sort them into the correct places.

You can use the worksheets that's provided, or you could just draw your circles and label them yourself just like the one on the screen.

So this one is a triangle.

Pause the video now, have a go at that activity and then come back and we'll check through them together.

How did everybody get on? Did you get the same answers as me? Let's have a look.

The first circle says is a triangle, and the next one is not a triangle.

All of those shapes in that circle of the triangle are triangles because they've got three sides, and three vertices.

Even though they're trying to trick us by being different colours and positioned in different ways they are still triangles.

And the ones on the other side, are not triangles because they don't have three sides.

All of those have got four sides, so the properties do not meet those of a triangle.

Fantastic sorting everybody.

I hope you all had a lovely time learning today.

Just before you go and complete your quiz, who do we need to wake up? We need to wake up Hedwig who was being very silly at the start of the lesson twisting her head around.

Now Hedwig, because you slept all the way through that lesson we're going to explain to you what we did.

Let's have a think everybody.

What did we learn today? Well we used our knowledge to describe 2-D shapes using mathematical language.

And then we used that knowledge to sort the shapes into groups depending on their properties.

So we identified whether they were triangles or whether they weren't triangles, do you understand? She does understand, really great learning today everybody well done see you very soon.