# Lesson video

In progress...

Hi, I'm Miss Kidd-Rossiter, and I'm going to be taking today's lesson on Exchange rates with graphs.

We're mainly going to focus on currency, but we'll also do a little bit on distance.

Before we get started, please make sure you're in a nice comfortable place, ready to get going, you've got all the equipment that you need, so you might find a ruler helpful for this lesson, and that you have no distractions.

If you need to pause the video now to sort anything out, then please do.

But if not, let's get going.

Today, let's try this activity then, you've got a graph on your screen showing the rate of exchange between pounds and euros.

How many ways can you complete the sentences? Pause the video now and have a go at this task.

Excellent work.

Well done.

Now, you can see that the easiest point to use is this one here.

For every six euros, we get five pounds because otherwise we're having to read smaller parts of the graph, which gets a bit trickier.

So you then could have used multiples of five and six to fill out the sentences in multiple ways.

So for every 25 pounds, for example, I get 30 euros.

The rate of exchange, we're going to come on to shortly.

And we know that six euros is equal to five pounds.

So we can put that in our table here.

Five pounds is equal to six euros.

So that means that we can work out what one euro is by dividing by six.

So that means that one euro is equal to 5/6 of a pound.

So one euro is 5/6 of a pound.

And we know that 5/6 is equal to 0.

83 recurring, but that's a bit tricky with money, isn't it? So it'd be 83 P to the nearest penny, but it's actually 83 1/3 pounds per euro.

We could also work out what one pound is by dividing six by five.

So one pound is 6/5 of a euro, and this one is slightly nicer because 6/5 is one euro 20.

So one pound is equal to one euro 20.

So that means you can see we've got our constant of proportionality going down the table.

So we're multiplying by 1.

2.

Five multiplied by 1.

2 gives us six.

5/6 multiplied by 6/5, we're multiplying by the reciprocal, so that gives us one.

And one multiplied by 1.

2 gives us one euro 20.

So that means that our exchange rate is one euro 20 per pound.

We could write it the other way, of course.

We could say that it's 5/6 of a pound per euro.

Excellent work.

So pause the video here, navigate to the independent task.

And when you're ready to go through some answers, resume the video.

Good luck.

Let's go through the independent task then.

So we're going to look at converting 20 Australian dollars to pounds.

So we find 20 on the Australian dollars axis, which is the y axis, and we draw across until we meet our line.

And then to convert it into pounds, we would go down until we meet the x-axis.

Now, this is quite a tricky one because it doesn't meet the line on an exact coordinate.

So if you said anything between eight pounds 80 and eight pounds 90, that would be fine for that one.

If you worked out exactly, I'll come back to what it would be in a second.

How many Australian dollars is one pound worth? Well, for me to do this, I first looked at two pounds because I can see on my graph that that is an exact coordinate on my graph.

So you would have used a ruler here, but I can say that two pounds is equal to \$4.

50 in Australia.

So that means that one pound would be worth \$2.

25.

For working out how many pounds, one Australian dollar is worth, I found it helpful to use this point here.

So it won't draw across and down, but you should have done.

That tells me that nine Australian dollars is equal to four pounds.

So that means to work out what one Australian dollar is.

It would be four pounds divided by nine, which gives us 44.

4 recurring pounds but I'm going to just round it to the nearest penny and say it's a 44 P.

so the exchange rate will be \$2.

25 per pound.

So let's just go back to this one again, 20 Australian dollars.

So if we know that we've got 20 Australian dollars, we can do our 44.

4 recurring pounds multiplied by 20, which gives us eight pounds 88 recurring.

So to the nearest penny, it would be eight pounds 89.

Convert 400 pounds to Australian dollars.

Well, if I know that four pounds is 9 dollars, I know that 400 pounds would be 900 dollars.

Use the graft to workout the following.

10 feet to metres.

So I'm going to find, 10 feet on my Y axis, draw a cross to my line and draw down.

This one is a little bit simpler.

So 10 feet is three metres.

How many metres is one foot then? So if I know that 10 feet equals three metres, one foot I've divided by 10, haven't I? So that would be 0.

3 metres or 30 centimetres.

How many feet is one metre? So to go from three metres to one metre, I would divide by three.

So that means that it'd be 10 thirds of a foot or 3.

3 recurring feet.

What is the conversion rate? So the conversion rate is not 0.

3 metres per foot and convert 300 metres to feet.

Well, if we know that three metres is 10 feet, then we know that 300 metres would be 1000 feet.

Let's have a look at the Explore task now then.

So we've got three days of conversion rates on the screen.

Your job is to figure out what is the best stage to exchange your pounds for euros.

Zaki exchanged his pounds for euros on day one, but then cancelled his holiday and exchange them back to pounds on day three.

What happened to his money? Pause the video now and have a go at this task.

Excellent.

Let's go through it together then.

So on day one, we know that we can use this point here, where we're told that 10 pounds converts to nine euros.

So that means that one pound is worth 90 cents and that also means that euro is worth one pound 11 to the nearest penny.

On day two, This is the one that we've already looked at.

We know that six euros is equal to five pounds.

So that means that one pound is one euro 20 and one euro is 83 P to the nearest penny.

And then day three, we can use the point here, where we're told that five pounds is equal to seven euros, which means that one pound is giving us one euro 40, or one euro would give us 71 P to the nearest penny.

So, we can see that the best day to convert pounds to euros, would be day three.

If we're going from pounds to euros, we would want to use day three because we're getting the most amount of euros for our pounds.

The best day to convert euros into pounds would be day one because we are getting the most amount of pounds for our Euro.

Now, if Zaki went on holiday on the first day, oh sorry, if Zaki changed his money on the first day, let's say that he exchanged a hundred pounds.

So a hundred pounds would give him 90 euros.

Yeah, hopefully you agree with that.

Then on day three, he's got to change them back.

So 90 euros, if we use our exact calculation here rather than the 71 P, it's now 0.

714285, where all of those decimal places recur, then his 90 euros would now be worth 64 pounds 29 to the nearest penny.

So you can see that the value of Zaki's currency by using different exchange rates has gone down.

So it started with a hundred pounds.

it's now down to 64 pounds.

That's the end of today's lesson.

So thank you very much for all your hard work.

Don't forget to go and complete the end of lesson quiz so that you can show me what you've learned and hopefully I'll see you again soon.

Bye.