# Lesson video

In progress...

Hi everyone, my name is Ms Sabzvari and I'm really excited you decided to join me today for a Maths lesson.

The unit that we're studying is Time.

In the previous lesson, we focused on sequencing daily events.

In this lesson, we will be calculating the duration of time in minutes.

So, when you're ready let's begin.

Let's have a look at today's lesson agenda.

First, we'll begin by calculating the end times of events.

Then we'll move on to a talk task.

After that we'll be calculating the duration of events and finally you will complete your independent task.

And before we begin today's lesson, you will need the following items. You will need something to write with and something to write on.

You will need a clock and you will need a ruler.

So please pause the video now and get the items that you need.

Calculating end times.

So let's have a look at the word problem on our screen.

Jay started the race at 20 past two.

He finished 10 minutes later.

What time did he finish the race? So what I would like you to do is to pause the video and tell your screen what is known and what is unknown.

Do that now.

Great job.

So we know what time Jay started the race.

What time does he start? Tell your screen.

Great work 20 past two okay? And the race lasted for 10 minutes.

How do you think we can work that out? What is the answer? And I want you to tell the screen and I want you to tell me how you worked it out.

Do that now.

Good job.

So, we know that the race finished at half past two okay? If Jay started at 20 past two and the race lasted 10 minutes.

So from 20 past two, we need to count 10 minutes on our clock okay? So five, 10 okay? So the minute hand is going to be on 30 the minute scale.

Lets have a look at another watch problem.

Mike started the race at 20 past two okay? So this is the time he started the race.

He finished 15 minutes later.

What time did he finish the race? What I would like you to do is the pause the video, tell the screen what is known and what is unknown.

What are we trying to work out? And I would like you to show the end time on your clocks.

If you don't have one, please draw a clock on your piece of paper and draw the hands on that.

Do that now.

Great job.

So Mike, started the race at 20 past two okay? And he finished 15 minutes later, so from 20 past we're going to count in fives until we reach 15 minutes okay? So five, 10, 15.

So we know that Mike finished the race at 25 to three okay? Great job If you got that correct.

Lets have a look at another watch problem.

Ella started the race at 20 past two.

She finished 20 minutes later.

What time did she finish the race? I would like you to do is to pause the video and to show the time on your clock.

Great job.

So Ella started at 20 past two and she finished 20 minutes later.

So from 20 past two, we are going to count in fives until we reached 20 minutes.

So let's do that together, five, 10, 15, 20.

So Ella finished the race at 20 to three.

Great job, If you got that correct.

So moving on to a talk task, what I would like you to do is to show the start time on your clock okay? Like we have been doing so far.

Then I would like you to count the duration in five minutes into those okay? And then I would like you to say the finish time out loud okay? But I would also like you to make a little note of it down.

So once we come to check our answers, you know what you got okay? So showing the time on your clock and working out the end time and jotting it down.

Do that now.

Great job.

Let's have a look at the answers.

So Lisa;s start time was 20 past six okay? As we can see here and the duration of the race for Lisa was 10 minutes.

So she finished 10 minutes after two from 20 past six, we're going to count in fives until we reach 10.

And that is her end time.

So are you ready? Five, 10, so Lisa finished the race at half past six.

Great job.

Let's have a look at Becky.

So Becky start time was 20 past seven okay? And her race lasted 10 minutes.

Again, from 20 past we going to count in fives until we reach 10.

Are you ready? Let's do it together.

Five, 10.

Great job.

So Becky finished the race at half past seven.

And finally, let's have a look at James' time.

So James start time was at 20 past seven too.

And his race lasted for 15 minutes okay? So from 20 past, we are going to count in fives until we reach 15.

Are you ready? Five, 10, 15 okay? So James finished the race at 25 to eight.

Great job, if you got all of that correct? Calculating duration of events.

Great job.

So let's have a look at the table okay? Again, we have a table with all runners and this time we don't know the start time okay? We know how long the race was going on for and we know the end time but we don't know what time they started.

That's what we're trying to work out okay? And what I would like you to do is to have a think about how can we work out what time the runners started the race? So pause the video now and share your answer with the screen.

Great job.

Okay, so the best way to do that is to show the end time on our clocks okay? And then count backwards the amount of minutes to see what time we started on okay? So what I would like you to do now is to pause the video and to work out the start time.

Do that now and then we'll go through the answers together.

Great.

So the first one, Lisa her end time was 20 to nine okay? And the race went on for 40 minutes and we're trying to work out what the start time was.

So, what I need to do is to make sure that i show the end on my clock.

So 20 to nine.

So I'm going to make sure that my clock is showing.

So, this is nine o'clock, 20 minutes to, so five, 10, 15, 20.

So this is 20 to nine and the race went on 40 minutes and this is the time that it ended.

So I'm not going to go this way okay? I'm going to to go backwards.

I'm going to go anticlockwise okay? So I'm going to start from here and I'm going to count in fives until I reach 40.

Are you ready? Five, 10, 15, 20, 25, 30, 35, 40 Okay? So the start time for Lisa, was eight O'clock.

Great.

Now, looking at Becky, Becky's end time was 20 to nine okay? So I need to make sure that my clock is showing 20 to nine okay? And the race went on for 35 minutes and again I'm trying to work out what the start time was.

So again, I'm going to go backwards 35 minutes.

So five, 10, 15, 20, 25, 30, 35.

So well, the start time for Becky was five past eight.

Great work.

And moving on to James.

Again, James start time we don't know.

So we're trying to work out using the duration and the end time.

So the end time for James was five to 10.

So I'm going to show five to 10 on my clock like this okay? And the race lasted 15 minutes.

Again, I'm going to go backwards to find what time he started on.

So five, 10, 15.

So the start time for James was 20 to 10.

Great job.

So as we just discussed, Lisa's start time was eight o'clock, Becky's start time was five past eight, and James' start time was 20 to 10.

Great work everybody.

So let's have a look at the table.

This time we know the start time and we know the end time.

But what we don't know is the duration that's right.

Is the duration how long the race lasted for? So what I would like you to do is to pause the video and to have a think about how can we work out the duration of the race? Do that now.

Great work.

So what we could do is, we could show the start time on our clock and then we could also point to the end time on our clock and then count or skip count in fives until we reach the end time okay? So what I would like you to do is to work out the duration of the races for Sarah and Alex.

So this time, what we're working out is the duration of how long the race went on for? We know the start time and we know the end time.

So what I'm going to do is I'm going to show the start time on my clock.

So Sarah's start time was quarter to five okay? I'm going to show a quarter to five on my clock.

So this is five o'clock and this is quarter to five.

And I know that the race ended at five to five okay? So five to five, this is where five to five is.

So I'm going to skip counts until I get to five to five.

Five, 10, so I know the duration of the race was for 10 minutes.

I'm looking at Alex's time.

I know that the start time for Alex was quarter to five as well okay? And he finished the race at five o'clock this time.

So I'm going to skip count in fives until I get to five o'clock okay? Five, 10, 15.

Great job.

So as we've just discussed, Sarah's race lasted for 10 minutes and Alex's race lasted for 15 minutes.

Brilliant job.

So moving unto our independent task.

What I would like you to do is to fill in the missing values on the race table.

Use your clocks to calculate the answers and then I would like you to draw the minutes and hour hands on the clocks okay? Or to write down if the end time is missing or if the start time is missing.

Great, let's have a look at the answers together.

So we know that Lisa's start time was 20 to eight and the duration of the race was 20 minutes.

So from 20 to eight, we're going to skip count in fives until we reach to 20.

Are you ready? Five, 10, 15, 20.

So the end time for Lisa was eight O'clock.

Great job.

Now Becky, we didn't know the start time, but we knew what time it finished and we knew how long the race went on for.

So we had to work backwards.

So, we would show the time five past eight on our clocks okay? And then we're going to count backwards in 20 minutes.

So five past eight okay? In 20 minutes, so five, 10, 15, 20 okay? So the start time for Becky would be quarter to eight.

Great job.

And Finally James, James' start time was 20 past four okay? And the duration we have to work out and it finished at five to five okay.

So am going to make sure I start from 20 past and I stop at five to five Are we ready? Let's get counting together, five, 10, 15, 20, 25, 30, 35.

I need to stop there, so the duration lasted up 35 minutes.

Great work if you got all of that correct.