# Lesson video

In progress...

Hi, my name is Mrs. Behan and I will be your teacher in this lesson.

In this lesson, we are going to help out.

Mr. Slade Mr. Slade is a teacher who is taking his class on a trip to London.

So being on time is going to be very important in making sure that the trip runs smoothly.

Are you ready to help out? Let's go.

Let's start by looking at the lesson agenda.

We're going to solve time related problems throughout the lesson.

We're going to take a look at Roman numerals.

We're then going to practise working out time intervals.

At the end of the lesson there'll be an independent task for you to have a go out.

I know you want to find out how you got on.

So I'll go through the answers with you.

There are just a couple of things that you will need for this lesson.

Something to write with, so a pencil or a pen and some thing to write on.

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

I remember try to work somewhere quiet where you won't be disturbed.

So this is Mr. Slade and his class of children and it's quite obvious to see where they are.

They are in London.

There were things that show us that they're in London like the London bus.

We can see Big Ben over here too and a sign post that shows the Underground.

So it's obvious that they are in London.

I wonder what they will get up to.

Have you ever been on a trip to London before? Well, Mr. Slade has run into a few problems to do with time and he does need our help.

So let's see how we can help him.

To travel from St.

James' Park to Westminster Bridge the group can travel in different ways.

So the first job is to get from one part of London to another and they can travel in different ways.

There's some options here.

The group can walk and it will take them 22 minutes to walk from St.

James's Park to Westminster Bridge.

Or they could get on the tube.

So if they travel by tube, it will take 15 minutes and then there is a nine minute walk once they've got off the tube at the other side.

Mr. Slade wants to take the children on the fastest route.

So how should they travel? Just have a little think.

Well, we know that this 22 here represents our walking time.

That is less than 15 plus nine, which is the combined number of minutes it would take if the group wanted to go on the tube.

So we can say, 22 is less than 24.

So if we know 22 is less than 24, which option is quicker? The group should walk because 22 minutes is a shorter amount of time than 24 minutes.

And Mr. Slade wants to go the fastest route possible.

How many minutes difference is there? There's only two minutes difference.

That's right.

The children have noticed that the clock on Big Ben looks different to any clock that they've seen before.

Just have a look of the picture.

What do you notice? Well, it's not a digital clock, is it? It is an analogue clock.

But around here we can't see number one, two, three, and so on.

Or can we? Well, actually the numbers are represented here but these are called Roman numerals.

So we can see one, two, three and so on all the way up to 12.

Let's have a closer look.

So, here is a clock showing Roman numerals.

This is a little bit clearer than the Big Ben picture.

So I want you to imagine now that we've got numbers one, sorry, 12 going all the way around to 12.

So one starts here all the way around to 12 like we would have a normal clock that we use.

This is how the numbers look like if we were to unravel a clock that had Roman numerals on it.

Can you count with me? It just starts from one and goes up to 12.

Let's count together.

One, two, three, four, five, six, seven, eight, nine, 10, 11, 12.

Let's count those again.

You may notice some similarities between some of the digits.

One, two, three, four, five, six, seven, eight, nine, 10, 11, 12.

So you might've noticed that we've got letters used.

I, V and X in there.

So depending on the way that those letters are arranged, they represent different numbers in Roman numerals but we like to use these numbers here.

Why don't you have a go at reading time on a clock that shows Roman numerals.

Pause the video here whilst you work out the times.

When you're ready, come back and I'll go through the answers with you.

So did you manage to work out the times on the clocks? It's quite straightforward really, isn't it? The first clock shows three o'clock.

The next clock shows seven o'clock.

And the final clock shows 10 o'clock.

Well done.

You never fail to impress me.

You can now read time when Roman numerals are used on a clock.

Fantastic.

We have a problem though.

Mr. Slade has broken his glasses and he can't see out to Big Ben.

Can you help him by matching the Big Ben displays to the clocks that you see underneath? This is what he'll be wearing his watch so we'll be able to see those.

So just take a moment, what to match with the times.

Did you have a go? Did you use your finger on the screen to try and match them off? Well, you might not be able to read time properly or really quickly on a Roman numerals clock, but a bit of a trick would be to look at the position of the hands.

So if I look at the position of the hands I can see that this first clock will match up to this clock here.

The hands are both in the same position.

They indicate the same time.

And what time does the clock indicate? It indicates four minutes past 12.

What's about the second clock? What time does this show? Well, it shows 25 minutes past 10.

And our final clock.

Can you read the time to me? Did you say 10 minutes to 11? Well done.

So now you can read the hour hand and the minute hand on the Roman numeral clock.

Well done.

Okay then, let's see what the next problem is to help Mr. Slade with.

Mr. Slade lets the children know that lunch will be at half past 12 but the children don't have analogue clocks on their watches, they have digital displays.

So have a look at these displays and see which time shows half past 12 so that they can have lunch.

Have you work it out? Let's go through each one.

Do we think it could be this one, 12:30 AM? Well, that means 30 minutes past 12.

So that's half past 12, but AM, ante meridiem, or before midday.

Would we ate our lunch before midday? Probably not.

I think this time has shown us half past midnight.

Let's look at this quite down here, 12:30.

Well, this doesn't say whether it is AM or PM.

So we don't actually know what time of day is showing.

Some watches don't have AM or PM on them though.

So it could be this one.

Let's look at this clock, 12:30 PM.

So half past or 30 minutes past 12:00 PM, post meridiem, or after midday.

Do you think it could be this one? What about this one, 30:12? Could it be 30:12? Well, this display showing 12 minutes, past 30 hours.

That doesn't seem right at all.

We would probably see this sort of display on a stopwatch because we know there are not 30 hours in one day.

So the correct answer is this one here, 12:30 PM.

Fantastic.

The children now gets gone on an exciting boat trip for their lunch.

So they are currently at Westminster Pier.

Then they're going to go on the river and spend some time at Greenwich Pier.

They're going to stay there for a while and then they're going to get on the boat back to Westminster Pier.

I would like to know how long the children can spend at Greenwich Pier.

How long did the children have at Greenwich Pier? Let's think about the information we need to get off this ticket here.

So Westminster Pier to Greenwich Pier departs at 12:38 PM, that's when they leave.

They go on the boats and they arrive at Greenwich Pier at 12:48 PM.

Then to come on their way back down to Westminster Pier, they have to get on the boat at 2:24 from Greenwich Pier down, and then they go on the boat for 10 minutes to Westminster Pier.

They arrived back at 2:34.

So let's think about the information that we actually need here.

I'm going to use a timeline and you'll be able to help me with this because I know you're good at using timelines.

Which is the important information from the ticket? Well, it's important to know what time they arrived at Greenwich Pier and what time they have to leave Greenwich pier.

Because between the times of them arriving at Greenwich Pier and leaving Greenwich Pier, that's the time they can have to spend there.

So let's pop those times in our timelines.

You can see 12:48 PM and 2:24 PM.

Let's put our hours in between now.

So we will pass 1:00 PM and we will pass 2:00 PM.

Does that mean the children get two hours there? That's not what it means.

By doing this in our timeline it just means that we can break up that long time interval into shorter time intervals which helps us calculate the whole time.

So how long does it take to get from 12:45 to 1:00 PM? How much time passes? Well, 12 minutes passes because four, to get from 48 to 60, which is when it's the change of the hour, 12 minutes passes.

To get from 1:00 PM to 2:00 PM, one hour passes.

And to go from 2:00 PM to 2:24 PM, 24 minutes passes.

Can you quickly total what that time for me? You should've got something that's like this, one hour plus 24 minutes plus 12 minutes is equal to, let's say it together, one hour and 36 minutes.

So the children get to spend one hour and 36 minutes at Greenwich Pier.

It's now time for you to have a go at the Independent Task.

Have a go with solving some more of Mr. Slade's problems Because there's quite sorts of texts on the screen I will read each problem to you.

Problem one.

The group took a guided tour around Buckingham Palace.

The tour started at 3:20 PM and finished at 4:05 PM.

How long was the tour? Problem two.

The group see a poster for the musical "Matilda".

It starts at 7:30 PM and finishes at 10:15 PM.

How long does the show last? Problem three.

The head teacher wanted to know what time the group would leave and return from the trip.

Show these times on a digital clock.

Remember AM and PM.

Problem four.

What time was it? Pause the video here whilst you complete your task.

When you're ready, come back to me and we will go through the answers together.

Well done for having a go at solving some more of Mr. Slade's problems. Let's look at problem one.

So the group got to take a guided tour around Buckingham Palace.

How exciting.

The tour started at 3:20 and finished at 4:05.

The tour lasted 45 minutes.

I know that because there are 40 minutes between 3:20 and 4:00 and five minutes between 4:00 and 4:05.

So, 40 plus five is 45.

Problem two.

So they see a poster for the musical "Matilda".

It starts at 7:30 and finishes at 10:15.

The show last two hours and 45 minutes.

I know there are two hours between 7:30 and 9:30 and 45 minutes between 9:30 and 10:15.

So the show lasts two hours and 45 minutes.

Problem three.

Did you manage to draw the digital times? Your first clock should show the time 7:23 AM.

Because we know it's AM because they will be leaving in the morning.

And the second digital clock should show 4:40 PM because we know that the group will be returning in the afternoon.

What time was it? Well, Big Ben chimes every hour for the number of hours that shows the time.

So if it's one o'clock, Big Ben chimes once.

If it's two o'clock, Big Ben chimes twice.

So Big Ben must have chimed twice.

And if it's been 45 minutes since he chimed twice, the time now must be quarter to three.