# Lesson video

In progress...

Hello, my name is Mrs. Behan and for this lesson I will be your teacher.

Are you able to round? Have you rounded to multiples of 10 before? Well, in this lesson we are going to be rounding to multiples of 1,000.

Let's take a look at the lesson agenda.

We will be rounding using a beadstring, then we will round using a number line.

We will practise rounding to the nearest 1,000 and at the end of the lesson, there will be an independent task for you to have a go at.

I know you have a keen to find out how you got on so I will go through the answers with you.

For this lesson you will just need two things: something to write with, so a pencil or pen, and something to write on.

If you don't have those things at hand right now, just pause the video here whilst you go and get them.

Remember to work somewhere quiet where you won't be disturbed.

This lesson is all about rounding so we need to remind ourselves of what rounding looks like.

Let's take a number, we'll go with 17, and we want to round 17 to the nearest multiple of 10.

So, we are going to do this by imagining a number line.

You can see one on the screen if you can't imagine.

Then we need to put each multiple of 10 on the outside of number 17.

So, 10 sits on the left and 20 sits on the right.

We're now going to work out the gap between 10 and 17, which is seven.

17 is seven away from 10.

We now need to work out the gap on the other side of 17 so going up to 20.

That gap is 3.

So this helps us realise that 17 is closer to number 20 so we can round up.

17 rounded to the nearest multiple 10 is 20.

Let's take another number this time.

Can you tell me that number? 170; and this time we're not rounding to the nearest multiple of 10, we're going to round to the nearest multiple of 100.

So here's the number line again.

What do we need to put on either side? That's right! The multiples of 100 that are on the outside of 170.

So we have 100 and 200.

We now need to work out the gap between 100 and 170, which is 70.

What is the gap between 170 and 200? It's 30; so that helps us decide which number it's closer to.

170 is closer to 200; it's only 30 away.

So we can round, 170 rounded to the nearest multiple of 100 is 200.

In this lesson we are going to use beadstrings.

Now, we don't have actual beadstrings but we are going to use this image of a beadstring.

At the start, at the top of the beadstring, that represents zero and at the end, that represents 1,000.

So we are going to try and find some numbers on the beadstring.

You are going to need your finger and the screen for this.

Using your finger, can you try and find the bead that represents 100? Here it is! Each bead is not worth one; each bead is worth 10.

So, if each bead is worth 10, then the green arrow is pointing to the hundred position on the beadstring.

Let's have a go at finding 120.

It's not too far away is it? Here is 120 on the beadstring.

Oh, this is a tricky one; 530.

Where is 530 on the beadstring? Have a look.

530 would be this one here.

What about 850? Where is 850 on the beadstring? There it is.

So we found lots of numbers on the beadstring now.

Which arrow is closest to 1,000? That's right; 850.

The green arrow pointing to 850 is closest to 1,000.

Which arrow is closest to zero? That's right; the light green arrow, 100 is closest to zero.

That's going to help us think about which is closer to zero and which numbers are closer to 1,000.

Okay, at the start of this beadstring we're going to say number 1,000 but at the end of the beadstring is 2,000.

You can see the beadstring is exactly the same and is still 1,000 beads between in value between 1,000 and 2,000.

So if we know that this is 1,010, I'm giving you that as a starting bead, where is 1,340 then? Can you find it using your finger? That's right; there it is.

There is a gap after this one.

1,340.

We moved three sets of 100: 100, 200, 300 so we are now 1,300.

1,300, 1,310, 1,320, 1,330, 1,340.

Is 1,340 closer to 1,000 or 2,000? It's closer to 1,000.

There are fewer beads between 1,340 and 1,000.

There are more beads between 1,340 and 2,000.

So what does that tell us about rounding? Well, 1,340 can be rounded to 1,000; just because it's closer to 1,000.

Let's have a go at this example: 1,670.

Where is that on this beadstring? Did you find it? Here it is.

1,670.

Is 1,670 closer to 1,000 or 2,000? If you need to pause the video to work it out then that is absolutely fine.

Just join in when you're ready! So there is fewer beads between 1,670 and 2,000.

So it's closer to 2,000.

So 1,670 can be rounded to 2,000.

Let's have one more go.

Here it is.

This is obvious to see which number- which number- it is closer to.

Is 1,880 closer to 1,000 or 2,000? It is closer to 2,000.

So say this with me: So 1,880 can be rounded to 2,000.

So I'm going to show you some place value counters now.

And I want you to think: which two multiples of 1,000 does 2,060 sit between? So here are the counters: 2,060.

Well, the next multiple of 1,000 would be 3,000 and the multiple of 1,000 that we've already passed is 2.

000.

So 2,000 and 3,000 sit either side of 2,060.

Over to you now.

Decide which two multiples of 1,000 these numbers sit between.

Pause the video here whilst you have a go and when you're ready come back and we'll look at the answers together.

Okay then, did you get that 2,000 and 3.

000 sit either side of 2,100? What were the missing numbers in these two boxes? 4,000 and 5,000.

What about here? 6,000 and 7,000.

This side: 4,000 and 5,000.

2,000 and 3,000.

And 7,000 and 8,000.

Remember, it doesn't really matter what the hundreds, tens, and ones, look like if we're rounding to a multiple of 1,000.

We're only interested in the thousands digit.

I would like to round 3,452 to the nearest multiple of 1,000.

How can this number line help me? Well, let's put the multiples at either side of this number onto the number line.

So 3,000 and 4,000 have been put onto the number line.

Now, how can I estimate where 3,452 will go? Well, I have an idea.

Why don't we put in the halfway point between 3,000 and 4,000? Halfway would be 3,500.

That helps it- that helps make it a little bit easier now because I know that 3,452 is less than 3,500.

I am going to put my arrow round about here.

So what does that tell me about rounding? Well, I now know that 3,452 can be rounded to 3,000.

Let's look at another example.

Say the number on the screen.

2,750.

What multiple is going to go here? That's right, 2,000; and on the other side 3,000.

What can we put in the middle? Halfway would be around 2,500.

So that helps us decide whether 2,750 should be rounded up or down because I'm going to guess that 2,750 is here on the number line.

So we are closer to 3,000.

We are all this distance away from 2,000 but here we are quite close.

So we are going to round to 3,000.

So you can have another go.

Okay, take this number: 6,820.

Which multiples are going to go on the number line? 6,000 and 7,000 and halfway is 6,500.

Put your finger where you think 6,820 would go.

Is it near my arrow? 'Cuz that's where I think I- I would put it.

So- what does this tell us about rounding? Well, we're closer to 7,000 so 6,820 can be rounded to 7,000.

Do you think you can do one more example? Let's have a look.

4,480 would sit between 4,000 and 5,000.

What would go halfway? That's right, 4,500.

Do you think you can put your finger on where that number might be.

Where 4,480 might be? Just here.

So is this going to round to 4,000 or 5,000? It's very close to halfway it's still closer to 4,000 so we know that 4,480 can be rounded to 4,000.

Now that you are an expert on rounding to multiples of 1,000 here is your independent task.

Use the number line to round each number to the nearest multiple of 1,000.

So, you've got a statement here: 3,800 rounded to the nearest 1,000 is: and you have to fill in that missing number.

Now, on these number lines you've got some markers on here.

So, I've put in for this first example 3,000 and 4,000 because those are the multiples of 1,000 either side of 3,800.

You can actually use this to work out where 308- 3,800 is and then you'll know which number you're rounding to: whether you're rounding to 3,000 or 4,000.

On the other examples you will need to put the multiples of 1,000 in.

When you're ready come back to me and we will look at the answers together.

So 3,800 rounded to the nearest 1,000 is 4,000.

It's only 200 away.

On the second example, the multiples you should've put on your line were 2,000 and 3,000 and you will realise that 2,167 is rounded to 2,000.

7,152 rounded to the nearest 1,000 is 7,000, we rounded down- it's closer to 7,000.

8,726 rounded to the nearest 1,000 is 9,000.

6,031 rounded to the nearest 1,000 is 6,000, it's only 31 away.

And 8,578 rounded to the nearest 1,000 is 9,000 and your number will have sat somewhere close to here, I would've thought.