Lesson video

Hello, everyone.

And welcome to maths with Ms. DobroWolski.

For those of you who have seen me before, it's really nice to see you again.

And for those of you joining our lessons for the first time, welcome.

In this unit, we're studying all about money and in today's lesson, we'll be learning about giving change.

Have a look at today's lesson agenda.

First, we'll be learning about subtracting units of money.

Then we'll have our top task, followed by some problem solving.

And finally, you'll be off your independent task.

For this lesson.

You will need a pencil and a notebook or something to write on.

If you don't have these items, pause the video now and go get them.

Remember to resume when you're ready.

Great, so let's review, one pound, hmm.

How many pennies are equal to one pound? Have a think and tell your screen.

That's right, one pound is equal to a 100 pence or 100 pennies.

So let's work out how much change we could get from one pound and knowing that one pound is equal to a 100 pence is really going to help us here.

So I have some items that I'd like to purchase from the shop.

If I want to buy this bag of apples for 95 pence, how much change would I receive? Well, if I pay with one pound and the cost is 95 pence, I simply do some subtraction, a 100 pence take away 95 pence is equal to five pence.

So if you think you're ready to find the change for the rest of these items on your own, you can pause the video now, complete the task resume when you're ready.

So you can compare answers.

If you're not feeling super confident, stay on with me and we can do it together.

So onto the next item, here we have a pencil and the cost is 60 P.

Remember I'm paying with one pound or a 100 pence.

And I know that my whole is 100 pence, so I'm simply going to subtract from the whole.

100 pence take away 60 pence is equal to 40 pence.

And for the comic, I'm going to follow the same process.

I know that I'm paying with a pound, which is equal to a 100 pence.

So I'm going to subtract the price from the whole.

A 100 pence take away 85 pence is equal to 15 pence.

And finally this lemon, Oh, I think it's a lemon fizzy drink has the cost of 80 pence.

So again, I know my whole is 100 pence, so I'm going to subtract 80 from 100, 100 pence minus 80 Pence is equal to 20 pence.

So well done everyone.

That was a really good review.

Let's move on.

Mh what happens when we don't have the exact coins to pay for an item? Well, as we've just realised, we have to get some change.

So I've gone to the shop and in my purse, I took 50 pence with me.

I bought an apple for 10 pence.

How much change did I receive? Well, there's two ways we can work this out.

And I put this beat string here for you to help you.

I know that my whole is 50 pence because that's what I'm paying with.

So my bead string has a value of 50 pence, 10 20, 30, 40, 50.

Now, if I know that 50 pence is my whole, there's two things I can do here.

I can calculate the change two ways.

The first is by counting up from the price of the item.

I know the price of the item is 10 pence, but I will start at 10 and count up to 50.

The amount that I count is going to be my change.

One thing I really like about this question is that I know these are all tens.

So instead of counting one, two, three, four, I'm simply going to count in tense.

It's really important that you're counting with me because I'm going to need some help.

So let's start at 10 and skip count 10, 20, 30, 40.

So I counted up and I needed 40 pence to reach 50.

So that means 10 pence plus 40 pence is equal to 50 pence.

My change is 40 pence because that was the part I was missing when I counted up.

Now, the other way we can do this is we can subtract from the whole.

So let's look at that.

Now I know that my whole is 50 pence.

So I'm going to subtract the price of the item, which is 10 pence.

So we start at 50 and let's count pence that we're going to take away, oh, well that's easy.

I know that this is already in tense.

So I'm going to get rid of this set of red beads because that's 10 beads, goodbye, okay.

50 pence take away 10 pence is equal to 40 pence.

That's what I have left over 10, 20, 30, 40, so 40 pence is my change.

Let's try another one.

If you're feeling super confident, you can pause the video now and worked out the change.

But if you're not quite sure, just stay on with me and we can do it together.

So what happens when we don't have the exact coins to pay for an item? Well, again, we need to get some change.

So again, I've gone to the shop.

I paid with my 50 pence coin for an item that costs 30 pence, hmm.

How can I work this out? Well, I've given you two strategies.

We can either count up or we can subtract from the whole, let's have a look.

Here's my bead string.

And the first thing I'm going to do is I'm going to try the counting up method just to practise.

So remember we start at the price of the item, which is 30, and we're going to count all the way to 50.

And remember, because these beads are groups of 10.

I can just skip down by 10 and make my life easier.

So skip count with me okay.

10 20 ah, if I start at 30, I only need 20 more pence to get to 50.

So 30 P plus 20 P is equal to 50 P.

My change then is 20 P let's try the other way.

We can also calculate change by subtracting from the whole.

I know that my whole is 50 pence.

What I'm going to subtract is the price of the items. So I need to subtract 30 from 50.

So let's try that together now, we need to skip count.

So skip count with me.

10, 20, 30 okay.

If I take away 30 I'm left with 20, 10, 20.

So 50 pence minus 30 pence is equal to 20 pence.

That's my change.

Can you see how, when we count it up, and when we subtracted, we got the same answer both times.

So that lets us know that we're correct, because we got the same answer using two different strategies.

It is now time for your talk task.

So what I want you to do is I want you to calculate the change that you would receive if you paid for each of these items with a one pound coin.

To help you, I've put the bead string here at the bottom of this screen.

And this bead string is equal to 100, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100.

And that's because one pound is equal to a 100 pence.

So if you need the bead string on the screen, it's there to help you.

So let's do the first one together.

So we all know what to do.

I'll start with the Apple.

I will buy an apple for 10 pence and I will pay with a one pound coin.

One pound is greater than 10 pence, so I will need to get change.

So I know my whole is 100 pence.

So I'm going to subtract 10 pence.

So 100 minus 10, and now I'm going to count how much I have left over, 10, 20, 30, 40, 50, 60, 70, 80, 90.

The change is 90 pence, great.

Your turn calculate the change you would receive for each of these items. If you paid with a one pound coin, when you're ready, don't forget to resume and we can go over the answers together.

Well done everyone.

So hopefully you've completed your talk task and you're ready to go over the answers.

So we know the change for the apple was 90 P.

Here for the candy, a 100p takeaway five P is equal to 95p, a 100p takeaway 30p for the pencil is equal to 70p.

For the ice cream, a 100 P takeaway 85p leaves you with 15p and 100p takeaway 5p is 95p again for the lollipop.

For the rubber that had a cost of 40p you would subtract 100 subtract 40p leaves you with 60p.

For the lemon fizzy drink, a 100p take away 80p is equal to 20p and for the banana, a 100p take away 20p leaves you with 80p change.

Well done everyone.

Now, we're going to deepen our thinking a little bit and do some problem solving.

So what strategy would you use to solve the following problem? I went to the shop and I bought an Apple for 35 pence.

I paid with a 50 pence coin.

How much change do I receive? Well, there's a couple of things we can do here.

The strategy I would use is first deciding what is my whole? Well, I know that my whole is 50 and one of my parts will be 35 because that's the cost of the apple.

So I'll draw my whole part model.

My whole is 50, one of my parts is 35 and whatever this has a value of will be my change.

So what I'm going to do, I'm going to use the strategy of counting up from 35.

I love when there's a digit of five or a zero in the ones column, because that means I can either skip count by my fives or tens, which I find really easy.

So what I did when I counted up is exactly that I skipped counted by fives and tens.

I know that 35 plus five is equal to 40, 40 plus 10 is equal to 50.

So if I add five plus 10, that's equal to 15, I would receive 15 pences change.

Now let's try another problem.

If you feel really confident, feel free to pause and work out the change by yourself.

But if you're not feeling super confident, just stay on with me and we can do it together.

So I went to the shop, I bought some carrots for 75 pence and I paid with one pound.

How much change do I receive? If you know the answer or you know how to figure it out? This is where you pause.

Well, first I'm going to identify my whole.

I know my whole is worth one pound or 100 pence.

And one of my parts is equal to 75 pence.

So here's my whole part model.

Again, my whole is 100, my part is 75.

I now need to figure out what my other part is going to be.

Well, this is the strategy I used.

Again.

I counted up, I know that, 75 plus five is equal to 80, 80 plus 10 is 90, 90 plus 10 is equal to a 100.

So five plus 10 plus 10 is equal to 25.

I would receive 25 pence change.

Let's try one more.

And this time we'll use our pound note.

So what strategy would you use to figure this out? I went to the shop and I bought a pedal for 15 pound and paid with a 50 pound note.

How much change do I receive? If you know the answer or you know how to get to the answer, pause now and then resume so we can compare answers if you're not feeling super sure, again just stay on with me.

So first I need to identify my whole and my whole is that's right 50 pounds.

My part is that's right, 15 pound.

So I will draw my whole part model.

Again, my whole is 50 pounds and my part is 15 pounds.

Now I need to figure out my other part that will help me get to 50.

Well, for this one, I did something a little bit different.

I know that the number 15 can be partitioned.

That means I can split the number 15 into my tens and ones.

I will use subtraction.

I know that 10 plus five is equal to 15.

I partitioned that number into a 10 and a five.

So 50 take away 10 is equal to 40 and 40 take away five is equal to 35.

So I would receive 35 pounds change.

Again, I started from my whole and I used subtraction.

I still subtracted 15.

I just did it in smaller bits.

That made sense to me.

So again, I would receive 35 pounds in change after I subtracted 50 take away 15.

It's already time for your independent tasks, wow.

So what I'd like for you to do here is to calculate the change for each example, you can use any strategy you think makes sense.

So if you prefer counting up or subtracting, that's your decision.

You can use one strategy for all of them, or you can try out different strategies depending on what you think is sensible.

So there's four questions here.

Make sure you read the questions thoroughly and you know whether your change is going to be in pounds or pence, make sure you checking if you're paying in pounds, or if you're paying with pence, it's really important that you double check that.

So again, you pause the video, complete your independent task, and you can resume the video when you think you're ready so we can check the answers together.

So again, you're calculating the change for each question and you can use any strategy you'd like.

Good luck, and I'll see you for the answers.

Great, so hopefully you've finished your independent task and we can go over the answers together.

For number one you went to the supermarket and bought a comic that costs 99 pence and paid with a one pound coin.

So for number one, 100 take away 99 pence is equal to one pence.

For number two, I went to the supermarket and bought a book that costs four pounds and paid with a 20 pound note.

So 20 pounds minus four pounds is equal to 16 pounds of change for number three, I went to the supermarket and bought a pack of sweets that costs 17 pence and paid with a 50 pence coin.

So 50 pence minus 17 pence is equal to 33 pence.

And finally, I went to the supermarket and bought a radio that costs 39 pound.

And I paid with a 50 pound note, 50 pounds minus 39 pounds is equal to 11 pounds of change.

Well done, everyone.

If you'd like to, you can share your work with Oak National, by asking a parent or care to share your work on Twitter, tagging @OakNational and #LearnwithOak.

Before you go, don't forget to complete your quiz.

It was really nice to see all of you and I really hope to see you for future lessons, bye.