Lesson video

Hello everyone.

Welcome back to another maths lesson with me, Mrs. Pochciol.

As always, I can't wait to learn lots of new things and hopefully have lots of fun.

So let's get started.

This lesson is called, "Subtract 4-digit Numbers using Column Subtraction," and it comes from the unit, "Column Addition and Subtraction with 4-digit Numbers." By the end of this lesson, you should be able to subtract 4-digit numbers using column subtraction, regrouping hundreds, tens and ones.

Here are this lesson's key words.

Column subtraction.

And regrouping.

Let's practise them.

My turn, column subtraction.

Your turn.

My turn, regrouping.

Your turn.

Fantastic.

Column subtraction is a way of subtracting numbers by writing a number below another.

The process of unitizing and exchanging between place values is known as regrouping.

For example, 10 tens can be regrouped as 1 hundred.

1 hundred can be regrouped as 10 tens.

This knowledge is really going to help us with our learning today, so let's get started.

Let's have a look at our lesson outline.

In the first part of our learning, we're going to be subtracting 4-digit numbers using column subtraction, and in the second part of our learning, we're going to solve problems involving 4-digit numbers.

So let's get started with subtracting 4-digit numbers using column subtraction.

In this lesson, you're going to meet Sam, Sofia, Izzy and Lucas.

They're going to help us with our learning.

Are you ready? Let's get started.

Izzy and Sofia calculate 215 subtract 113 using base 10 blocks.

Izzy really can't remember how to do this, but Sofia's going to help her.

The tens digit of the subtrahend is greater than the tens digit of the minuend.

Oh no, so what do we have to do? We have to regroup one of the hundreds as 10 tens.

Sofia explains how to do this.

We're going to start by representing 215 using our base 10 blocks.

We're gonna start with the ones.

5 ones subtract 3 ones is equal to 2 ones.

Now, in our tens column, 3 tens is greater than 1 ten, so we can't subtract it.

So we're going to regroup one of the hundreds as 10 tens.

There we go.

Now we have 11 tens.

So 11 tens subtract 3 tens is equal to 8 tens.

And 1 hundred subtract 1 hundred is equal to zero.

We can see that we have 8 tens and 2 ones left.

So 215 subtract 133 is equal to 82, and Izzy is feeling much more confident and remembers how to regroup now.

They now represent this as a column subtraction.

215 subtract 133.

We need to start with the numbers in the smallest place value.

So that's the ones.

5 ones subtract 3 ones is equal to 2 ones.

Remember, in the tens column, the digit of the subtrahend is greater than the tens digit of the minuend.

So we're going to regroup.

We're going to regroup 1 hundred as 10 ones.

So we've got 1 hundred left and now we have 11 tens.

11 tens subtract 3 tens is equal to 8 tens.

And 1 hundred subtract 1 hundred is equal to no hundreds.

So we can see that 215 subtract 133 is equal to 82.

Well done Izzy, and thank you for helping, Sofia.

Izzy and Sofia now look at a different problem.

Hmm, what do you notice here? Izzy thinks that we can use column subtraction for this problem, but Sofia's not sure if we can because they are now 4-digit numbers.

Who do you agree with? Sofia suggests that we could try to use column subtraction to see if it works.

So let's have a go.

Izzy and Sofia first represent the calculation using base 10 blocks.

So they're going to represent 6,285 using the blocks.

Are we ready? 6 thousands, 2 hundreds, 8 tens and 5 ones.

First, we're going to subtract the ones.

5 ones subtract 8 ones, we can't do that, so we're going to regroup 1 ten as 10 ones.

There we go.

Now we have 7 tens and 15 ones.

So 15 ones subtract 8 ones is equal to 7 ones.

7 tens subtract 3 tens is equal to 4 tens.

Sofia notices that the hundreds digit of the subtrahend is greater than the hundreds digit of the minuend.

Yes, because we can't subtract three from 2 hundreds, can we? So what are we going to have to do? That's not a problem.

We just need to regroup.

So we're going to regroup 1 thousand as 10 hundreds.

So now we have 5 thousands and 12 hundreds.

12 hundreds subtract 3 hundreds is equal to 9 hundreds.

And 5 thousands subtract 2 thousands is equal to 3 thousands.

We can now see that we have 3,947 left.

Well done Izzy and Sofia, but I think it could be more efficient for us to use our column subtraction.

Shall we have a go? We need to start with the smallest place value, which is our ones.

And remember, 5 ones subtract 8 ones.

We couldn't do that, so we had to regroup.

We can regroup 1 ten as 10 ones.

So now we can see we have 7 tens left and 15 ones.

15 ones subtract 8 ones is equal to 7 ones.

7 tens subtract 3 tens is equal to 4 tens.

Remember in our hundreds column, the digit of the subtrahend is greater than the hundreds digit of the minuend.

Two subtract three, we can't do that, so we've had to regroup.

We can regroup one of the thousands as 10 hundreds.

So we now have 5 thousands and 12 hundreds.

12 hundreds subtract 3 hundreds is equal to 9 hundreds.

And 5 thousands subtract 2 thousands is equal to 3 thousands.

We can see that we now have 3,947.

So we can say that 6,285 subtract 2,338 is equal to 3,947.

Let's check to see if this is the same answer that we got with our base 10 representation.

3 thousands, 9 hundreds, 4 tens and 7 ones.

Yes, it's the same, 3,947 is our answer.

Well done, Izzy, and well done, Sofia.

Okay then, over to you then with your first check.

Represent this calculation using your own column subtraction to find the difference.

6,637 subtract 3,779.

Remember, if a digit in the minuend is smaller than the digit in the subtrahend, you will have to regroup.

So look out for this.

Pause this video, find the difference using column subtraction, and come on back to see how you've got on.

Welcome back, let's have a look then.

First thing we need to do is to represent our numbers on our column subtraction.

So we have 6,637 subtract 3,779.

Now we can calculate.

Remember, we start with the smallest place value numbers first, which is our ones.

7 ones subtract 9 ones, we can't do that, so we need to regroup one of the tens as 10 ones.

We now have 2 tens and 17 ones.

17 ones subtract 9 ones is equal to 8 ones.

2 tens subtract 7 tens, we can't do this, so we need to regroup 1 hundred as 10 tens.

We now have 5 hundreds and 12 tens.

12 tens subtract 7 tens is equal to 5 tens.

5 hundreds subtract 7 hundreds, we can't do that, so we need to regroup 1 thousand as 10 hundreds.

We now have five thousands and 15 hundreds.

15 hundreds subtract 7 hundreds is equal to 8 hundreds.

And 5 thousands subtract 3 thousands is equal to 2 thousands.

So we can see that the difference is 2,858.

Well done to you if you got that correct.

Lots of regrouping there.

I hope that didn't trip you up too much.

Izzy and Sofia now look at this problem.

Hmm, what do you notice? Izzy has noticed that we have a 4-digit number and a 3-three digit number.

Can we subtract a 3-digit number from a 4-digit number using column subtraction? What do you think? I think we should have a go.

Are we ready? 7,249 subtract 568.

Remember to place 568 in the correct columns.

It has 5 hundreds, 6 tens, and 8 ones.

It doesn't have any thousands, so it has to go there on our columns.

Are we ready? Let's get calculating then.

9 ones subtract 8 ones is equal to 1 one.

4 tens subtract 6 tens.

We can't do that, so we have to regroup.

We can regroup one of those hundreds as 10 tens.

So we now have 1 hundred and 14 tens.

14 tens subtract 6 tens is equal to 8 tens.

1 hundred subtract 5 hundreds.

We can't do that, so we're gonna have to regroup again.

We can regroup one of those thousands as 10 hundreds.

So now we have 6 thousands left and we now have 11 hundreds.

11 hundreds subtract 5 hundreds is equal to 6 hundreds.

And 6 thousands subtract zero- because remember 568 doesn't have any thousands.

So 6 thousands subtract zero thousands is equal to 6 thousands.

So we can see that 7,249 subtract 568 is equal to 6,681.

So we can use column subtraction if we have a 4-digit and a 3-digit number.

Well done, Izzy and Sofia.

Now it's over to you.

Represent this calculation using your own column subtraction to find the difference.

3,467 subtract 942.

Remember, if a digit in the minuend end is smaller than the digit in the subtrahend, you will have to regroup.

Also, make sure that you pop 942 in the correct columns.

Pause this video and come on back when you've found the difference.

Welcome back, let's see how you got on.

3,467, and remember, 942 has 9 hundreds, 4 tens and 2 ones.

So it has to go there, there's no thousands.

Now we can calculate.

7 ones subtract 2 ones is equal to 5 ones.

6 tens subtract 4 tens is equal to 2 tens.

No regrouping there, wow.

4 hundreds subtract 9 hundreds.

Oh, we can't do that, so we have to regroup.

We're regrouping one of those thousands as 10 hundreds.

So we now have 2 thousands and 14 hundreds.

14 hundreds subtract 9 hundreds.

We can do that now, which we know is equal to 5 hundreds.

And 2 thousands subtract no thousands, because there isn't any in 942, is equal to 2 thousands.

So we can see that 3,467 subtract 942 is equal to 2,525.

Well done to you if you got that correct.

Over to you then with Task A.

Task A is to roll your dice to create your own subtraction and solve this using column subtraction.

Sofia's going to show us how to create her subtraction.

First she rolls a two.

So in the roll one she can see that that represents 7,655.

Then she rolls a five, which in roll two, we can see that represents 9,835.

So she's now got 7,655 and 9,835.

She's now going to create a subtraction.

We know that we can't subtract 9,835 from 7,655.

So we're going to swap the numbers around and solve 9,835 subtract 7,655.

So if your rolls give you a smaller number and a larger number, you can swap them around so that you can still complete the subtraction using column subtraction.

Pause this video, have a go at Task A and come on back when you're ready to see how Sofia got on with solving her problem.

Welcome back, I hope you're feeling so much more confident with your column subtraction now.

Shall we see how Sofia got on with her calculation? 9,835 subtract 7,655.

Remember, we're going to start with the smallest value first, which is our ones.

5 ones subtract 5 ones is equal to zero ones.

3 tens subtract 5 tens.

We can't do that, so we're going to have to regroup.

We regroup 1 hundred as 10 tens.

We've now got 7 hundreds and 13 tens.

13 tens subtract 5 tens is equal to 8 tens.

7 hundreds subtract 6 hundreds is equal to 1 hundred.

And 9 thousands subtract 7 thousands is equal to 2 thousands.

So we can see that 9,835 subtract 7,655 is in fact equal to 2,180.

Well done Sofia, well done Izzy, and well done to you for completing Task A.

Let's have a look at the second part of our learning.

So now we've practised using column subtraction we're going to solve some problems involving 4-digit numbers.

Are we ready? Let's get started.

Izzy, Sofia, Sam and Lucas visit their local arcade for a fun day out.

The children played on nearly every game in the arcade and won lots of tickets.

Wow, look at how many tickets they've won.

With all their tickets, the children visit the ticket shop to spend all the tickets that they have won.

Oh, look at that.

It's got so much cool stuff in it.

Lucas doesn't know what to pick.

He thinks he's going to get the sunglasses.

They are 746 tickets.

Lucas has 8,375 tickets altogether.

So how many tickets will he have left after buying the sunglasses for 746 tickets? Hmm, I think we can work this out using column subtraction.

Are we ready? 8,375 tickets, that's how many Lucas has got and 746, that's how many he's using to buy the sunglasses.

So let's see how many he'll have left.

5 ones subtract 6 ones, we can't do that.

So we're going to have to regroup.

Now we have 15 ones subtract 6 ones which is equal to 9 ones.

6 tens subtract 4 tens is equal to 2 tens.

3 hundreds subtract 7 hundreds.

We can't do that, so we're going to regroup.

We now have 13 hundreds subtract seven hundreds, which we know is equal to 6 hundreds.

7 thousands subtract no thousands is equal to 7 thousands.

We can see that Lucas will have 7,629 tickets left and some very cool shades.

Wow, look at those, Lucas.

They look fabulous, well done.

Sofia says that she has 1,794 tickets left.

So Izzy is trying to work out which item she's bought.

Hmm, Sofia had 3158 tickets and now she's got 1,794.

Izzy thinks that it has to be the ball or the robot.

The robot would leave Sofia with closer to 1000 tickets, so Izzy's leaning towards the football.

She's going to calculate to see if that's correct.

3,158 is the number of tickets that Sofia started with.

1,364 is the cost of the ball.

Izzy's going to subtract that amount from the whole and if it leaves her with 1,794, she knows that Sofia must have bought the ball.

Are we ready? Ones first, then.

8 ones subtract 4 ones is equal to 4 ones.

5 tens subtract 6 tens.

We can't do that, so we're going to regroup.

15 tens subtract 6 tens, we can do that, that's 9 tens.

Zero hundred subtract 3 hundreds.

We can't do that, so we're going to regroup.

And we now have 10 hundreds subtract 3 hundreds which is 7 hundreds.

And 2 thousands subtract 1 thousand is equal to 1 thousand.

Yes, 1,794 tickets left.

So that means Sofia did buy the football because 3,158 subtract 1,364 is equal to 1,794.

Well done Izzy, and I hope you enjoy that ball Sofia.

After spending some of their tickets in the ticket shop, the children now compare the number of tickets they have left.

How many more tickets does Sam have left than Izzy? Hmm, how are we gonna work this out? We know that to find out how many more, we need to find the difference and the difference is the result of a subtraction.

Sam has more tickets.

So if we subtract Izzy's number from Sam's number, that'll show us the difference.

5,923, Sam's number subtract Izzy's number, which is 5,630, will give us the difference.

And how many more? So let's set this up on our column subtraction.

5,923 subtract 5,630.

Let's calculate.

3 ones subtract zero ones is equal to 3 ones.

2 tens subtract 3 tens.

We can't do that, so we have to regroup.

12 tens subtract 3 tens is equal to 9 tens.

8 hundreds subtract 6 hundreds is equal to 2 hundreds.

And 5 thousands subtract 5 thousands is equal to zero thousands.

That means that the difference between Sam and Izzy's number of tickets is 293.

So Sam has 293 more tickets than Izzy.

Well done guys.

Over to you then.

How many more tickets does Lucas have than Sofia? Lucas notices that he has more tickets than Sofia.

So he suggests that if we subtract Sofia's number of tickets from Lucas's number of tickets, they will be able to find the difference.

Pause this video, complete your column subtraction and come on back when you can tell me how many more tickets Lucas has than Sofia.

Welcome back, so let's see how you got on.

5,629 subtract 1,794.

That will give us the difference.

9 ones subtract 4 ones is equal to 5 ones.

2 tens subtract 9 tens.

Now we can't do that, so we're going to regroup.

12 tens subtract 9 tens, we can do that, that's 3 tens.

5 hundreds subtract 7 hundreds, we can't do that, so we're going to regroup 1 thousand as 10 hundreds.

15 hundreds subtract 7 hundreds, we can do that.

That's equal to 8 hundreds.

And 4 thousands subtract 1 thousand is equal to 3 thousands.

So we can see that the difference is 3,835.

We can see that the difference between Sofia and Lucas's number of tickets is 3,835.

So Lucas has 3,835 more tickets left than Sofia.

Goodness me, that is a lot of tickets, isn't it? Over to you then with Task B.

Task B, Part One.

Each child adds up how many tickets they have left and buys one more item from the ticket shop.

How many tickets will each child have left after buying these items? Izzy buys a lovely hat, Sofia buys a panda bear.

I think I'd buy that one.

And Lucas buys a new piggy bank, probably to keep all those tickets in, hey Lucas? Part Two.

After buying their final items, who has more tickets? Lucas or Izzy? What is the difference between their number of tickets? And Part Three.

Sam has 5,923 tickets.

She bought one item and has 4,991 tickets left.

Which item did Sam buy? Use the column subtraction to check that you are correct once you've chosen the item.

Hmm, which one did Sam buy? So pause this video, have a go at Part One, finding out how many tickets they have left.

Part Two, finding the difference between Lucas and Izzy's remaining number of tickets.

And Part Three, exploring which item Sam must have bought to have 4,991 tickets left.

And come on back once you've had a go at all three.

Welcome back.

Let's have a look then at how we got on.

Part One.

How many tickets did each child have left after buying these items? Izzy bought that lovely cap for 1,254.

She had 3,471 tickets left after buying that.

Well done if you've got that one.

Let's remind ourselves what Sofia bought.

She bought that lovely panda bear.

That panda bear was 969, which was a 3-digit number.

So hopefully you put that in the correct place on your column subtraction.

Let's have a look.

Oh, lots of regrouping there.

Regrouping in the ones needed and in the hundreds, and she would have 825 tickets left.

So well done if you got that one.

And finally, Lucas bought that piggy bank, a very expensive piggy bank there, 3,237 tickets.

After buying that, he would still have 2,392 tickets left.

Well done to you if you've got those three correct.

Now let's have a look at Part Two.

Part Two.

We wanted to find the difference between Lucas and Izzy's number of tickets.

So Izzy had 3,471 tickets left and Lucas has 2,392 tickets left.

Izzy had more tickets, so we needed to subtract Lucas's number from Izzy's number, which was 3,471 subtract 2,392.

We needed to regroup here.

So 11 ones subtract 2 ones is equal to 9 ones.

6 tens subtract 9 tens.

We need to regroup again.

Goodness me, lots of regrouping today.

16 tens subtract 9 tens, that's equal to 7 tens.

3 hundreds subtract 3 hundreds is equal to no hundreds and 3 thousands subtract 2 thousands is equal to 1 thousand.

We can see that the difference is 1079 tickets.

So that means that Izzy has more tickets.

The difference between the number of tickets was 1079.

So well done to you if you got that correct.

Part Three was to work out which of the items Sam bought with her tickets.

Lucas had a go at working this one out.

Lucas noticed that there was less than 1000 difference, so she must have bought something that was less than 1000 tickets.

The number subtracted was close to 1000.

So Lucas thinks that it must be the figurine for 932 tickets rather than the lollipop for 436.

Lucas now uses his column subtraction to check that he's correct.

3 ones subtract 2 ones is equal to 1 one.

2 tens subtract 3 tens.

We couldn't do that, so we have to regroup.

12 tens subtract 3 tens is equal to 9 tens.

8 hundreds subtract 9 hundreds.

We can't do that so we need to regroup.

18 hundreds subtract 9 hundreds is equal to 9 hundreds.

And 4 thousands subtract no thousands is equal to four thousands.

Yes, 4,991 tickets left.

So she must have bought the figurine.

Is that correct, Sam? Yes, Lucas, it was the figurine, well done.

Sam is very impressed with your calculating there.

After thinking about this problem though, Lucas notices another way that he could have solved this problem.

He noticed that Sam had 4,991 tickets left, so he could have subtracted this known part from the whole of 5,923 and that would've showed him how many tickets Sam had used to buy the item.

Let's have a look then Lucas.

See if this can help you to find the same answer.

3 ones subtract 1 one, that's equal to 2 ones.

2 tens subtract 9 tens, we have to regroup here because we can't do that.

12 tens subtract 9 tens is equal to 3 tens.

8 hundreds subtract 9 hundreds.

We can't do that, so we have to regroup.

18 hundreds subtract 9 hundreds, that's equal to 9 hundreds.

And 4 thousands subtract 4 thousands is equal to zero thousands.

We can see that Sam spent 932 tickets.

932 tickets is the cost of the figurine, so it must be the figurine.

Is he correct, Sam? He is correct.

Well done Lucas for finding two different ways that you could have found out what Sam had bought.

Well done to all of our Oak children and well done to you for completing this lesson.

Let's have a look at what we've covered today.

Column subtraction can be used to subtract 4-digit numbers.

Work from the ones column on the right so that regrouping can be represented.

If the tens value of the subtrahend is greater than the tens value of the minuend, exchange 1 hundred for 10 tens.

If the hundreds value of the subtrahend is greater than the hundreds value of the minuend, exchange a thousand for 10 hundreds.

Well done for completing this lesson.

I'm hoping you're feeling a lot more confident with column subtraction with 4-digit numbers.

Thank you for joining me again, and I hope to see you all again soon.

Goodbye.