Lesson video

Hello, everybody.

My name is Mrs. Johnson.

I am so happy 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 as we learn new things.

Let's have a look at what we're going to be learning about today.

This lesson is called Compare and Order Length.

It comes from the unit Sense of Measure.

By the end of this lesson, you will be able to compare and order lengths.

You're going to be thinking about lengths that are longer or shorter than each other.

There are going to be some key words that are really important for this lesson.

We're going to practise saying them now.

My turn first and then your turn.

Ready? My turn, compare, your turn.

My turn, order, your turn.

Well done.

Listen carefully for those words today because they are really important for what you're going to be learning about.

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

To begin with, you're going to compare lengths, and then in a little while, you are going to order lengths.

Let's get started with compare lengths.

There are going to be two friends helping us in this lesson today.

Their names are Laura and Izzy.

Listen carefully to the things they have to tell you because they have some really helpful and important things to say.

Laura and Izzy are thinking about how they could compare lengths.

They could say the snake is longer than the worm.

The worm is shorter than the snake.

Now they have a mouse and a fox.

What could they say this time? The fox is taller than the mouse.

The mouse is shorter than the fox.

Let's check if you know how to compare heights and lengths of these different animals.

The cat is mm than the penguin.

The penguin is mm than the cat.

The crocodile is mm than the snake.

The snake is mm than the crocodile.

Use the words in the box to help you complete each sentence.

Pause the video and have a go now.

Well done.

Let's see if you are correct.

The cat is shorter than the penguin.

The penguin is taller than the cat.

The crocodile is longer than the snake.

The snake is shorter than the crocodile.

Good job If you said that.

A tree is six metres tall.

A plant is six centimetres tall.

Laura has noticed that they are both six, so she says the tree and the plant must be the same height then.

Do you think that's right? Izzy doesn't.

Izzy says, "I'm not sure that that's right.

Let's think carefully about how to compare these lengths." What does six m mean? It means that the tree is six metres tall.

That's right, and then six cm means six centimetres.

I wonder what you can remember about metres and centimetres.

Let's have a look.

One centimetre is about the length of a lady bug or the width of a paperclip.

One metre is about the height of a door handle or the width of a staircase.

If both measurements are six, but one is metres and one is centimetres, then that means that six metres must be longer because one metre is longer than one centimetre, so six metres must be longer than six centimetres.

Now we can compare the lengths.

The plant is shorter than the tree and the tree is taller than the plant.

We could say that six metres is greater than six centimetres, and six centimetres is less than six metres.

We could also use symbols to compare these lengths.

We could say six metres is greater than six centimetres and six centimetres is less than six metres using symbols.

Now it's your turn to have a go.

Let's check that you know how to compare two lengths in different ways.

A toy crocodile is five centimetres long.

A real crocodile is five metres long.

The toy crocodile is mm than the real crocodile.

Five centimetres is mm than five metres.

Five metres is mm than five centimetres.

At the bottom, you need to choose which inequality symbol to use in each box, greater than or less than.

Pause the video and have a go at that now.

Really good thinking, well done.

Let's see if you are correct.

The toy crocodile is shorter than the real crocodile.

Five centimetres is less than five metres.

Five metres is greater than five centimetres.

That means we can use these symbols.

Five centimetres is less than five metres and five metres is greater than five centimetres.

Well done if you got those correct.

You have just seen that when the numbers are the same, you can use the unit of measure to help you compare lengths.

Laura is thinking about how we could compare lengths when the unit of measure is the same but the numbers are different.

Izzy says, "Let's think about what we've learned before about comparing numbers." Let's have a look at that together.

Do you remember that you can represent numbers with base 10 blocks to help you compare them? Which number is greater? We have 43 and 29.

Let's have a look.

We're going to use the base 10 to help us find out.

10s are greater than ones, so we're not going to look at the ones.

We're just going to compare the 10s 43 has more 10s than 29, so 43 is greater than 29 because it has more 10s.

Izzy can remember a different strategy to compare numbers.

She can use a number line to help.

43 is greater than 29 because it comes later in the counting sequence when she counts to 43, she counts past 29.

Here's 29 and here's 43.

You can see that 43 is greater than 29 because it comes further along the number line, and 29 is less than 43 because it is not as far along the number line.

You could also use a table to help you compare numbers.

If you have 23 and 15, we're going to look at the 10s digits by putting them into a table.

We know that 10s are greater than ones, so the number with more 10s will be the greater number.

We're going to have a table with 10s and ones.

23 has two 10s and three ones, 15 has one 10 and five ones.

If the 10s are greater and the number with more 10s will be the greater number, we can see that two 10s is more than one 10, so 23 is the greater number.

We could also say that 15 is less than 23 because it has fewer 10s.

We know that you can use a number line to compare numbers.

When you count to 23, you count past 15.

There's 15 on our number line and there is 23.

That means that 23 is greater than 15 because it is further along the number line, and 15 is less than 23 because it is not as far along the number line.

We can show that using inequality symbols 15 is less than 23.

Laura's noticed something about this number line.

She says it reminds her of a ruler.

The scale on a ruler is just like a number line, so perhaps we could use the scale on a ruler in the same way that we use a number line to help us compare lengths.

The scale on a ruler is just like a number line, so it's really useful when you want to compare lengths.

Here's 15 centimetres.

Here's 23 centimetres.

You can see that 23 centimetres is greater than 15 centimetres because it's further along the scale on the ruler, just in the same way as it was further along on the number line, 15 centimetres is less than 23 centimetres because it is not as far along the scale on the ruler.

You can also compare lengths by looking at the number of 10s just like we did when we had two digit numbers.

Let's look at these lengths.

The Leaning Tower of Pisa in Italy is 56 metres tall.

In our table we can say that 56 has five 10s and six ones.

Tower Bridge in London is 65 metres tall.

That has six 10s and five ones.

Laura says, "I know that six 10s is greater than five 10s, so 65 metres is greater than 56 metres." Izzy says, "I could compare these lengths by saying that the Leaning Tower of Pisa is shorter than Tower Bridge." We could show this using inequality Symbols.

56 metres is less than 65 metres.

Let's check that you know how to compare lengths.

A plane is 51 metres long.

A boat is 49 metres long.

Can you compare these lengths to say which is longer and which is shorter? Pause the video and have a think now.

Good thinking.

Let's have a look at some of the different ways you might have thought about this.

You could say the plane is longer than the boat because 51 has five 10s and 49 only has four 10s.

The number with five 10s is greater, so 51 metres is longer than 49 metres.

You could write it with an inequality symbol to say that 51 metres is greater than 49 metres.

You might have also thought about seeing these numbers on a number line or putting the number of 10s and ones into a table.

Now it's time for you to practise comparing lengths.

First, you're going to think about this information.

A toy rocket is 70 centimetres tall.

A real rocket is 70 metres tall.

You need to decide who you think is correct and how you know.

Izzy says, "They are the same length because they are both 70." Andeep says, "The toy rocket is taller than the real rocket." Laura says, "The real rocket is taller than the toy rocket." Who do you agree with and how do you know? Next, you're going to choose a phrase from the box to compare each pair of lengths, so you need to choose from shorter than, longer than, or the same as to make each sentence correct.

Finally, you're going to write inequality symbols to compare each pair of lengths.

You need to write a greater than or a less than symbol in each box to help you compare the lengths.

Remember to look really carefully at how many 10s are in each number, and Izzy says, "Don't forget to check the unit of measure for each length." You're going to pause the video and have a go at those now.

Off you go.

Let's see how you've got on.

The first question told you that a toy rocket is 70 centimetres tall, and a real rocket is 70 metres tall.

Izzy said, "They're the same length because they're both 70." Andeep says, "The toy rocket is taller than the real rocket," and Laura says, "The real rocket is taller than the toy rocket." You should have realised that Laura was correct.

The numbers in each length are both 70, but the unit of measure is different.

One metre is longer than one centimetre, so a 70-meter height must be taller than a 70-centimeter height.

The real rocket is 70 metres, so the real rocket is taller than the toy rockets, which is only 70 centimetres.

Laura was correct.

Well done if you agreed with Laura.

Next, you needed to choose a phrase to compare each pair of lengths.

First, 60 metres is longer than 60 centimetres.

14 centimetres is shorter than 14 metres.

52 metres is the same as 52 metres.

They've written m for short, but we know that m stands for metres.

Five metres is longer than five centimetres, 40 metres is longer than 40 centimetres, and 16 centimetres is shorter than 16 metres.

Well done for thinking really carefully about which phrase you needed to choose each time.

Now let's see if you've written the correct inequality symbol in each box to compare each pair of lengths.

Izzy says, "If the unit of measure is the same, then the number with more 10s is greater." So that means that 47 metres is less than 74 metres, 18 metres is less than 81 metres, 68 centimetres is less than 72 centimetres, and 34 metres is greater than 29 metres.

When you got to the next one, you needed to think about something else.

Laura says, "When the numbers are the same, the unit of measure can help you to compare the lengths." Did you notice this one was 71 metres and 71 centimetres.

71 metres is greater than 71 centimetres, 50 metres is less than 60 metres.

25 centimetres is less than 55 centimetres, and six metres is greater than six centimetres.

Well done if you were able to compare each pair of lengths correctly.

Good job.

Now it's time for the second part of this lesson where you are going to think about how you can order lengths.

Laura and Izzy are thinking about how they can compare more than two lengths.

Now they have a snake, a worm, and a fish.

Laura knows that the snake is longer than the worm and the fish, and the worm is shorter than the snake and the fish.

Laura also knows that the fish is longer than the worm and shorter than the snake.

That means the snake is the longest and the worm is the shortest.

Now they're going to look at some heights of these buildings.

The house is the shortest building.

The school is shorter than the church.

Laura says that means the church is the longest building.

Do you think that sounds right? I'm not sure about that.

Izzy's going to help us out.

Izzy says, "When we're talking about height, we say the tallest not the longest." So the church is the tallest building.

Now let's look at the height of each building.

We could write these in order, starting with the shortest and going up to the tallest.

The shortest building is nine metres, then 16 metres, and 32 metres is the tallest height.

Izzy says we could write these length in order from the tallest to the shortest.

We would start with 32 metres, then 16 metres, and nine metres is the shortest.

When you order lengths, you can use the same strategies that you would use to compare lengths.

Laura likes to use a number line to help her order lengths like this.

She could say nine metres is here on the number line, and then 16, and then 32 metres.

Izzy knows that 32 metres is the tallest height because it is furthest along the number line, and nine metres is the shortest length because it comes before the other numbers on the number line.

Izzy says, "I don't like to use a number line.

I usually use a different strategy." Izzy likes to look at the 10s digits and the number with the most 10s will be the greatest.

So she uses a table and she shows the 10s and the ones.

The house is nine metres long, so it has no 10s and nine ones.

We don't need to keep that zero.

It's just nine ones.

The church has three 10s and two ones because it's 32 metres, and 16 metres for the school has one 10 and six ones.

32 metres has three 10s, so it is the longest length.

Nine metres has no 10s, so it is the shortest length.

You could also use symbols to show the order of lengths.

We could say that 32 metres is greater than 16 metres, and 16 metres is greater than nine metres.

We could write this the other way around and we could use the less than symbol.

Nine metres is less than 16 metres and 16 metres is less than 32 metres.

It's time to check that you know how to write lengths in order, which lengths are written in the correct order starting with the longest.

Pause the video and have a look.

Well done.

You had to look really carefully, didn't you, to work out which lengths are in the correct order.

You should have said that A is in the correct order.

Well done if you said A.

76 centimetres is the longest length because 76 has seven 10s, which makes it the greatest number.

27 is the shortest length because 27 has the fewest 10s, so the order needed to be 76 centimetres, then 67 centimetres, and then 27 centimetres.

Well done if you spotted that.

Let's have a look at another set of three heights, and think about ordering them.

An ash tree is 21 metres tall.

A silver birch tree is 16 metres tall.

An oak tree is taller than the silver birch tree, but shorter than the ash tree.

How tall could it be? So we don't know the height of the oak tree, but we do know that it's taller than the silver birch and shorter than the ash tree.

We need to work out how tall it could be.

Laura thinks that we might be able to use a number line to help with this problem.

Let's have a look.

The oak tree needs to be taller than 16 metres because it's taller than the silver birch, so let's put 16 metres on our number line, and it needs to be shorter than 21 because that's the height of the ash tree.

Let's put 21 metres on our number line.

That means that the oak tree needs to be one of these lengths here.

It needs to be between 16 metres and 21 metres, so it could be 17 metres, 18 metres, 19 metres or 20 metres tall.

The number line is really helpful for finding those missing lengths that the oak tree could be.

Let's check if you can solve a similar problem to that.

Andeep and Laura both have a piece of ribbon you can see here.

Izzy has a piece of ribbon too, but we can't see Izzy's ribbon.

Andeep's ribbon is the shortest and Laura's ribbon is the longest.

How long could Izzy's ribbon be? Pause the video and have a think.

Well done.

That's quite a tricky problem to think about, isn't it? We know that Andeep's ribbon is the shortest and Laura's ribbon is the longest.

That means that Izzy's ribbon needs to be longer than Andeep's, which is 22, but shorter than Laura's, which is 29.

You needed to decide which measurement is longer than 22 centimetres, but shorter than 29 centimetres.

You should have said 25 centimetres.

You could have used the number line on the ruler to help you find the missing lengths that the ribbon could be.

We know it needs to be longer than 22 and we know that it needs to be shorter than 29, so it could have been 23, 24, 25, 26, 27 or 28 centimetres long.

Good job if you thought about using your number line to help you too.

Now it's time for you to practise thinking about how you can order lengths.

First, you're going to think about a game that some children played.

They wanted to see how far they could kick a football and they recorded their results.

You can see the name of each person and how far the ball travelled when they kicked it.

You need to write the children's names in order starting with the person who kicked their ball the shortest distance.

Izzy says that you could use a number line or you could look carefully at the number of 10s in each number.

Next, you're going to have a look at their results again, but this time you are going to write the lengths in order using greater than or less than symbols.

Make sure you don't write the children's names this time.

You write the distance that the ball was kicked and you need to write them in order using the symbols.

Laura says you might be able to find more than one way to write these lengths using symbols to show the order.

After that, you're going to have another think about this game because what happened in this game was that another person came to join.

Her name was Sofia, and Sofia kicked the ball further than Laura, but not as far as Izzy.

You need to think about how far could Sofia have kicked the ball.

Izzy wants to know how many different answers you can find.

I wonder if you'll be able to find all of the possible answers.

You're going to have a go at writing one digit in each empty box so that these lengths are in order.

Look carefully at the symbols and think about whether they are less than or greater than to see whether the order goes from the longest to the shortest or from the shortest to the longest.

Laura wonders how many different answers you might be able to find.

You're going to go and try that now.

Get everything ready that you need.

Pause the video.

Off you go.

Let's see how you've got on.

First, you needed to think about writing the children's names in order.

Perhaps you might have used a number line to help you.

The distance Andeep kicked his ball was 27 metres, so you could find where 27 is on the number line and label Andeep.

Izzy's distance was 40 metres.

We could label Izzy here at 40.

Laura's distance was 31 metres, so she would be here, and Sam's distance was 19 metres.

Once you've labelled the children's names on the number line, you can see the order that they need to be in.

Starting with the shortest distance.

the order should be Sam, Andeep, Laura, Izzy.

Well done if you got those correct.

Next, you needed to think about how you could write the length in order using greater than or less than symbols.

You might have thought about starting with the shortest distance, and you could have written that 19 metres is less than 27 metres, 27 metres is less than 31 metres, and 31 metres is less than 40 metres.

Perhaps you wrote it the other way around like this.

You could have said 40 metres is greater than 31 metres, 31 metres is greater than 27 metres, and 27 metres is greater than 19 metres.

Well done if you thought about how you could start with the longest or the shortest distance.

Make sure that you did use the correct symbol to show the order of each length.

Then Sofia joined the game.

So you needed to think about how far could Sofia have kicked the ball.

We know it was further than Laura, and Laura kicked her ball 31 metres, so you could put 31 metres or Laura on the number line and Izzy's was 40, so you could put 40 or Izzy on the number line.

That means that Sofia could have kicked her ball on any of these lengths here.

So she could have kicked it 32 metres, 33, 34, 35, 36, 37, 38 or 39 metres.

Well done if you spotted all of those different possible answers.

Good job.

Finally, you needed to choose a digit that you could write in each empty box to make sure that these were correct and in the correct order.

There are lots and lots of different answers that you could have had for this one.

I am going to show you one way that you could have filled in each box.

We could have had 20 for the first one.

B, you could have written 60.

C, you could have written 55.

D, you might have written 16 E, you might have written 91.

And F, you could have written 70.

Did you look carefully at the symbol to work out whether your next length in the order was going to be greater than or less than the last one? Well done if you remembered to look really carefully at those symbols.

That's really important when you're comparing and ordering lengths.

Now that you're at the end of the lesson, you have learned that when you compare lengths, you find which length is longer or taller or shorter.

When you order lengths, you find which length is the longest, the tallest, or the shortest, and you can show a set of lengths in order.

You can start with the longest or the shortest length.

You know that when the numbers are the same, you can use the unit of measure to help you compare lengths.

When the units are the same, you can compare and order lengths in the same way that you can compare and order two digit numbers.

You also know that you can use greater than and less than symbols to compare and order lengths.

You have done some excellent work and thought really carefully about comparing and ordering length today.

Well done.

I hope that I'm going to see you again soon for some more maths learning.

Bye, everybody.