Lesson video

Hello everybody.

My name is Mrs. Johnson.

I am so excited to be here today to help you with some of your maths learning.

I hope you are ready to work hard and have lots of fun.

Let's see what we're going to be learning about today.

This lesson is called describe name and sort polygons, including triangles and quadrilaterals.

It comes from the unit shape.

Discuss and compare 2D and 3D shapes.

By the end of this lesson, you will be able to recognise and describe different polygons including triangles and quadrilaterals.

If you haven't heard of quadrilaterals before, don't worry.

It might be something that you have never learned about before until today, which is really exciting.

I will help you and by the end of this lesson you are going to be an expert on quadrilaterals.

There are four important keywords that we are going to practise to get you ready for this lesson.

I will say them first and then it will be your turn.

Ready? My turn.

Triangle.

Your turn.

My turn, quadrilateral, your turn.

I think we should practise that one one more time 'cause it's quite tricky to say isn't it? Ready, my turn quadrilateral your turn.

Well done.

My turn, rectangle, your turn.

My turn, square.

Your turn.

Good job.

There are going to be two parts to this lesson today.

To begin with, you are going to be learning all about triangles and then in a little while you are going to find out about quadrilaterals.

Let's start by looking at triangles.

There are going to be two friends in this lesson who are going to help.

Their names are Alex and Sam.

Listen carefully to the things that Alex and Sam have to tell you because they will be really important for your learning today.

Today Sam has cut out some different 2D shapes from card.

Sam says, I am going to show you some of the shapes that are triangles.

I wonder if you can imagine what are the shapes going to look like that Sam might show us? Let's have a look at them now.

These are all triangles.

What do you think about these triangles? So they look how you were expecting them to look.

Is that what you were imagining when you were picturing a triangle? Do you notice anything that's the same about all of these triangles? Let's have a look.

Sam says, all triangles have three straight sides and three vertices.

You can see that all of these triangles have three straight sides and three vertices, three corners.

Sometimes a shape can look a bit like a triangle.

You have to look really carefully at its properties to check if it's a triangle or not.

Sam says, properties could be the number of sides or the number of vertices.

Let's count the sides of this shape and see what happens.

One, two, three, four, five, six.

This shape has six sides.

We just learned that a triangle needs to have three sides.

That means if this shape has six sides.

It is not a triangle is it? It does look a bit like a triangle, but it has six sides, so it is not a triangle.

Now look at this one.

This shape looks a bit like a triangle too, but Sam says this shape has no straight sides.

It is not a triangle.

It has curved lines, doesn't it? A triangle must have three straight sides, so this is not a triangle.

It just looks a little bit like one.

What about this shape? What do we think? Sam says this shape has no vertices.

It is not a triangle.

Again, it does look like a triangle, but it is not a triangle because a triangle must have three vertices.

This shape has curved lines where it should have vertices, so it is not a triangle.

Let's check if you can spot which shape is a triangle.

Do you think it's A or B or C? Pause the video and have a think.

The shape that is a triangle is A, it cannot be B because B does not have vertices and it cannot be C because C does not have three straight sides.

I can see a curved line.

Here's another question for you to check that you are really good at explaining why a shape looks a bit like a triangle, but it is not a triangle.

How could you complete this sentence? This shape is not a triangle because, hmm, pause the video and have a think.

Here are some ways you might have completed this sentence.

You could say this shape is not a triangle because it only has one straight side.

You could have said this shape is not a triangle because it has two curved lines.

You could have said this shape is not a triangle because it has no vertices.

It does look like it has points on the corners which look a bit like vertices, but remember a vertex is where two straight sides join to make a point.

These are not straight sides, which means that this shape does not have any vertices.

A triangle needs to have three vertices.

You know that the name for all of these shapes is triangle, but Sam wants to know why are these shapes called triangles? What does the word triangle actually mean? Let's have a look.

You might have heard another word that starts with the same letters as triangle.

Have you heard of a tricycle before? What do we know about a tricycle? That's right.

A tricycle has three wheels.

Try means three.

Let's look at the other part of the word triangle.

Angle links with corners or vertices.

That means that the word triangle means three vertices.

We know that a triangle has to have three vertices, don't we? The name triangle is describing the properties of a triangle that it has three vertices.

Alex is going to sort these shapes into two sets.

His sets are called triangle and not a triangle.

Alex is remembering that a triangle has three straight sides and three vertices.

That's really important, isn't it? To help him sort these shapes into these two sets.

Let's watch him sort them now.

This one's not a triangle because it has a curved line.

This one is not a triangle because it has curved lines.

This one is a triangle.

This one is not a triangle because it has four sides.

This one is not a triangle because it has four sides.

This one is a triangle.

This one is a triangle.

This one is not a triangle because it has a curved line.

Let's check if you know how to sort shapes into sets.

Your sets are the same ones that Alex just used.

Triangle and not a triangle.

Have a go at sorting these shapes into those sets.

Pause the video and try and do that now.

Well done.

Let's have a look at how you should have sorted these shapes into the correct sets.

The first shape is not a triangle.

It does look a bit like a triangle, but if you count the sides really carefully, you will see that it has four sides.

The second shape is a triangle.

The next shape is not a triangle because it has curved lines.

The next shape is a triangle and the last shape is not a triangle.

It has six sides and six vertices, so it is not a triangle.

Now that you've had a go at sorting shapes into these sets, let's check if you can find the shapes that have been sorted into the wrong set.

Look really carefully and see if you can spot the mistakes.

Remember to think about how many sides and vertices a triangle should have.

Pause the video and see if you can spot any mistakes in this sorting.

Let's have a look and see if you've spotted all of the mistakes.

This shape has been put in the triangle set, but it is not a triangle because it doesn't have three vertices.

This shape has been put in the triangle set and this one's not a triangle either.

This shape has four sides.

It should not be in the triangle set.

It's not a triangle.

There is one more.

This one, well done if you spotted this.

This one has three straight sides and three vertices, so this one is a triangle, but it's been put in the not a triangle set.

Did you remember to explain this one is not a triangle because it has curved lines.

It doesn't have vertices.

This one is not a triangle because it has four sides.

This one is a triangle because it has three straight sides.

Well done if you spotted those mistakes and you could explain why they were in the wrong set.

Good job.

Now it's time for you to go and practise sorting shapes into sets.

You need to look carefully at how these shapes have been sorted.

First, you are going to write a label for each set of shapes.

You might need to think about this hint that Sam is giving you, which set contains triangles.

Then you are going to sort A, B, C, and D into the correct sets and finally you are going to draw some more shapes in each set.

Remember to think really carefully about how many sides and how many vertices a triangle needs to have.

You are going to sort these shapes now, off you go.

Well done.

This is how you could have sorted your shapes.

First, you needed to think about what you were going to call each set.

The first set has shapes that are not triangles, so you need to call this the not a triangle set.

The second set does have triangles, so this set can be called triangle.

Then you needed to sort A, B, C, and D into the correct set.

A is not a triangle, B is a triangle, C is not a triangle and D is a triangle.

Did you draw more shapes in each set? Let's have a look at what you could have drawn.

Maybe you drew something like this in the not a triangle set, something that looks a bit like a triangle but it is not a triangle.

Maybe you drew a triangle like this or like this.

Did you make sure that your triangles had three straight sides and three vertices? Well done for thinking so carefully about what is a triangle and what is not a triangle.

Excellent work.

Now it's time to have a look at the second part of today's lesson.

You are going to be learning about quadrilaterals.

I know you might not have heard of a quadrilateral before, but don't worry because you are going to find out all about it now.

Let's have a look.

We know that the word triangle means three vertices.

The name of the shape tells you about the properties of the shape.

I wonder what a quadrilateral is.

Is there part of that name that might give us a clue and tell us about the shape? Have you ever seen one of these before? This is a quad bike and a quad bike has four wheels.

I wonder if that gives us a clue about what quadrilaterals are going to have.

What do you think? There's another word that starts with quad.

Four brothers and sisters all born on the same day are called quadruplets, so a quad bike has four wheels and four baby brothers and sisters born on the same day are called quadruplets.

In the word quadrilateral, quad means four lateral means side, so the word quadrilateral means a shape with four sides.

The word is telling us about the properties of the shape just like the word triangle did.

Triangle meant three vertices.

Quadrilateral means four sides.

All of these shapes are quadrilaterals because these all have four straight sides.

Let's have a look at these quadrilaterals.

They all have four straight sides even though they don't all look the same, they do have four straight sides.

Some times a shape can look a bit like a quadrilateral.

You have to look really carefully at its properties to check if it's a quadrilateral or not.

This one is not a quadrilateral because can you see at the top of the shape it has a curved line.

Quadrilaterals have to have four straight lines.

This shape is not a quadrilateral.

It does look a bit like one, but this one is not a quadrilateral because this shape has five straight sides and a quadrilateral should have four.

Let's check if you can spot a quadrilateral.

You're going to look carefully at each shape as it appears.

If it is a quadrilateral, hold up four fingers like this.

If it's not a quadrilateral, keep your hands down by your sides.

Are you ready? Here's the first shape.

Well done, this is a quadrilateral.

You should be holding up four fingers.

Here's the next shape.

Good.

This one is a quadrilateral too it has four sides.

This one, no.

Well done.

Keep your hands down by your sides.

This one does not only have four straight sides.

It has eight.

This one.

Well done.

This one is a quadrilateral.

Let's see those four fingers.

Here's the next shape.

While done, keep those hands down.

That's not a quadrilateral that has more than four sides.

Here's the next one.

Well done.

This one is a quadrilateral.

It does have four sides.

Here's the next one.

Well done.

Four sides means it is a quadrilateral.

Here's the next one.

Well done.

Keep those hands down.

This one only has three sides.

This is not a quadrilateral.

This is a triangle.

Here's the next one.

Good.

This one is a quadrilateral and it does have four sides.

Here's the next one.

This one is not a quadrilateral.

It has five sides.

Keep those hands down.

Here's the next one.

Well done.

This one is a quadrilateral.

It does have four sides.

And here's the last shape.

This one is not a quadrilateral.

It does look like it has four sides, but remember that they have to be straight.

This shape only has two straight sides and it has two curved lines, so it's not a quadrilateral.

This shape has four straight sides.

This one is a quadrilateral.

Alex says, I know a different name for this quadrilateral.

I wonder if you know a different name for this shape.

Have you ever learned a different name for this shape? What would you call it? Let's see.

Some quadrilaterals can have other names too, so this shape is a quadrilateral, but this shape is also a rectangle.

Maybe that's the shape you were thinking of.

You might also call this shape an oblong.

All of those names are correct.

It could be called a quadrilateral.

It could be called a rectangle and it could be called an oblong.

Here's another example that some quadrilaterals can have other names too.

This shape looks similar to the last one.

This is another rectangle, but Alex says that I know another different name for this quadrilateral.

I wonder if you know it too.

This shape is a quadrilateral and a rectangle.

This shape is also a square because all four sides are equal in length.

Were you thinking of square two? Well done.

This shape is a quadrilateral.

This shape is a rectangle and this shape is a square.

They are all correct names for this shape.

Alex could sort these shapes into two sets.

His sets are called quadrilateral and not a quadrilateral.

Let's watch how he sorts them.

He's going to remember that a quadrilateral has four straight sides, so he says the first one is a quadrilateral.

It has four straight sides.

The next one is not.

The next one is not a quadrilateral because it doesn't have all straight sides.

The next one is not a quadrilateral.

It's a triangle, it only has three sides.

The next one is a quadrilateral.

The next shape is a quadrilateral.

The next one is not a quadrilateral because it has six sides and the last shape is a quadrilateral.

It has four straight sides.

Now, Alex could sort these shapes into different sets.

Now his sets are called rectangle and not a rectangle.

Alex says, I know that a rectangle has four straight sides and four square corners.

There is one shape that is not in the right set.

Can you see which one it is? Well done.

This shape is not a rectangle, so it needs to move into the not a rectangle set.

Now Alex's shapes are sorted correctly.

Alex is going to change the name of his sets again to sort them into two different sets.

This time he has called his sets square and not a square.

Alex says, I know that a square has four equal sides and four square corners.

Can you see which shape Alex needs to move this time because it's not a square.

Well done.

That's right.

It's this one, isn't it? That's a rectangle, but it is not a square.

Do you think Alex needs to move any more shapes? No.

You are right.

Alex's shapes are now sorted correctly.

Two of his shapes are squares and six of his shapes are not squares.

Let's check if you really understand about squares, rectangles and quadrilaterals.

Can you match the shapes to their names? Remember that a shape can have more than one name.

Pause the video and have a go at matching each shape to all of its names that would be correct.

You have thought really carefully about these important words.

Well done.

The first shape is a quadrilateral, but it's not a square and it's not a rectangle.

The second shape is a square and a rectangle and a quadrilateral.

You can use all three names to describe that shape.

The third shape is a square and a rectangle and a quadrilateral.

Sometimes people don't think this looks like a square because it is not sitting on one of its sides, but it is a square.

It's just been rotated, hasn't it? The last shape is a rectangle and a quadrilateral.

This one is not a square because not all the sides are equal in length, but it is a rectangle and it is a quadrilateral because it has four sides.

Now it's time for you to go and do a bit more practise.

You are going to complete this table to show the correct names for each shape.

The first shape has been done for you.

You can see they have put a cross next to square and across next to rectangle because this shape is not a square and it's not a rectangle, but they have drawn a tick next to quadrilateral because this shape has four sides, so this shape is a quadrilateral.

Can you draw the ticks and the crosses in the rest of the boxes to show which names are correct for each shape? You are going to choose one of these shapes and think about how many different ways you could complete Alex's sentence.

You are going to use our keywords, quadrilateral, rectangle, and square, and you are going to complete this sentence.

This shape is or is not a hmm because hmm.

Try and complete that sentence in as many different ways as you can for the shape that you chose.

Then you are going to draw your own shape and you are going to write a sentence just like Alex's to describe it.

You can choose if you would like your sentence to say, this shape is a mm or this shape is not a mm.

Then use the word because to explain how you know that your shape is or is not the name that you have chosen.

Remember that your key words are on your sheet, quadrilateral, rectangle, and square.

They are there to help you so that you remember that you need to choose one of those words to use in your sentence.

You are going to pause the video and go and complete those practise tasks now, off you go.

Well done.

Let's have a look at how you might have put in your ticks and your crosses to complete this table correctly.

The next shape in the table, if you looked at carefully, you can see that it does have four sides, but it is not a square because the sides are not all equal and it's not a rectangle because some of the vertices are not square corners, so you need to draw across in the square and across in the rectangle, but a tick in the quadrilateral because it does have four sides.

The next shape is not a square.

The sides are not all equal, but it is a rectangle because it does have four square corners and it is a quadrilateral.

The next shape is not a square and is not a rectangle and it's not a quadrilateral because it doesn't have four straight sides, so you need to put a cross in each box for that one, and the lash shape is a square, it is a rectangle and it is a quadrilateral.

So three ticks for the last shape.

Well done if you were able to remember which names you can use to describe each of those shapes.

On the second task, your sentences might have sounded a bit like this.

If you chose this shape, you could say this shape is a quadrilateral because it has four straight sides.

You could say this shape is a rectangle because it has four straight sides and four square corners.

You could say this shape is not a square because the four sides are different lengths.

It does not have four equal sides.

Maybe you didn't choose this shape.

Maybe you chose a different one like this one.

If you chose this shape, you could have said this shape is not a quadrilateral because it has eight straight sides.

You could have said this shape is not a rectangle because it has eight sides and no square corners.

Did you have a go at drawing your own shape and writing a sentence a bit like Alex's to describe it? You could have drawn something like this.

You might have said this shape is a quadrilateral because it has four straight sides.

You could say this shape is a square because it has four equal sides and four square corners.

Well done if you were able to think really carefully about the shape that you've drawn and whether you would be able to call it a quadrilateral, a rectangle, or a square, and you were able to give a reason why.

Well done.

Now that you are at the end of the lesson, you know that a triangle has three straight sides and three vertices.

You know that a quadrilateral has four straight sides and four vertices.

You have learned that some quadrilaterals have other names too.

A rectangle is a quadrilateral and a square is a quadrilateral too.

You have thought really carefully in this lesson today you have learned lots about triangles and quadrilaterals.

Well done.

I hope the time will see you again soon for some more maths learning.

Bye everybody.