Lesson video

Hello everyone? I'm Miss Brinkworth.

I'm going to be going through this math lesson with you today.

Should we have a look at our learning objective? What we're going to be doing is we're going to start having an understanding of area.

And as a measurement of a surface, that's measured using square units.

Now that's quite wordy, but today's lesson is just really an introduction to area, to really start thinking about how area is different to perimeter, and start thinking about how we measure it.

Okay.

So let's get started.

We'll look at our lesson agenda for today.

So like I say, we're going to introduce area.

So by the end of today's lesson, you'll have a really good idea of what we mean when we say area.

We're then going to think about how we calculate it, how we work out what it is.

How we measure it.

You are then going to have a chance for an independent task.

And there will be a quiz at the end of each to test what you've learned today.

Okay.

So, what you going to to need is pen or pencil, paper and ruler.

If you can't find a ruler 'cause you're at home, please don't worry too much.

It should be actually fine without one, but please pause the video here and get what you need for today's lesson.

Okay welcome back.

I hope you've got everything you need, so let's get started.

So here's a warmup.

And what I'd like you to do is to convert these measurements from metres, from centimetres and metres, just to send vice-versa from some are in centimetres, you need to change them to meet us, et cetera.

So you need to write the fraction down as well.

So think carefully about the relationship between metres and centimetres.

There are 100 centimetres in a metre.

So, for example if you're looking at two metres there, that is going to be 200 centimetres.

You've got one there as well which is 350 centimetres.

So, you've definitely got three metres because you've got 300 centimetres.

How will you write the 50 centimetres, when you're converting it just into metres.

So please please take your time with this, and think carefully about each one.

Okay let's see how you got on.

So here are the answers, well done if you got all of these correct.

So we are in the first two columns you're going from centimetres to metres.

So I mentioned that two metres is 200 centimetres, 350 centimetres is 3.

5 metres.

A way of thinking about that, is because 50 is half of a hundred.

So 50 centimetres is half of one metre.

And when we represent half as a decimal, like we're doing that it's.

5.

So 600, oh sorry, so 6,700 centimetres, we've got 67 metres.

We've moved into the next place value column in our centimetres, we not just in the hundreds, we're in the thousands, so that we've got tens of metres when we convert it to metres.

And again, hopefully you saw that pattern with 24 metres, because we're into the tens of metres when we move it to centimetres, because we're moving at two decimal places to the left, we're going to be into our thousands.

Here What are we doing centimetres as a fraction of a metre.

So you would given that 50 centimetres is half a metre.

25 is half of 50.

So half of half is a quarter.

75 is three quarters and 20 well done if you've got that one.

As a fifth.

Really great work there.

Okay, let's move on then.

We hopefully you feel quite confident with perimeter.

Perimeter being the distance around the boundary of a shape.

So to find the perimeter, we add together the length of all of the outside of a shape.

All of the sides, added together, gives us the perimeter.

And we measure that in length, centimetres or metres.

If we're talking about something very big, we might even talk about kilometres, but that's a normal distance measurement that we're measuring when we do perimeter.

Area is different.

Because area is the surface of the shape.

The space inside it.

The space it takes up.

We won't be able to measure that, in centimetres or metres.

Because that measures a line, a distance from one place to another.

Area is the surface of the inside of a shape.

Imagine you had a square and you coloured it in.

everything you coloured in, would be the area that, that square.

Okay.

So, have a think about which of these, you would measure as perimeter.

So the outside of a shape, which would be length.

So the one point to another and which would be area that's the surface inside a shape.

So pause over your hair and think for each statement.

What is being measured? Is it perimeter, length or area? Let's see how you got on.

Don't worry if you've made a few mistakes, these are quite tricky.

But this is what you should have had.

So the fencing to go around the playground, we'd want fencing to go all the way around the playground.

That would be perimeter.

How much carpet though is needed for a room? That would be the surface of the floor of the room.

So that would be area.

How long pencil is from the end to the end? That's a length.

How much wallpaper is needed for one of your bedroom walls? Area, you'd cover the whole surface in wallpaper.

How much border is needed for a classroom display? Well that would be perimeter.

And how far can a kangaroo jump from one place to another? Length.

Okay.

So, we've talked about what area is, how do we calculate it? Well one of the ways in which we can calculate area, is we can cut it up into small squares to help us work it out.

So here's a rectangle.

How many squares make up this rectangle? Can you see? Well, we've got four orange squares and four blue squares.

So we've got four add four.

No, my mistake.

Sorry, I counted those incorrectly.

There are five, there are five of each five blue and five orange.

So we've got 10.

You could see that as we've got two down the side and five across the top, not four, as I said.

Five across the top.

So we've got two, lots of five.

We've got 10.

And we write it like this units with a squared.

That means that it's taking up an area It's not just a distance from one line to another.

It's taking up area, that's the actual surface that is taking up.

Okay.

Have a go then, have an estimate, I know it's going to be might be a little bit tricky for you to do this on the screen, but work out how many of those little squares, you think would fill this big square.

You can estimate, what you think the area of this space shape might be.

Let's see how you got on.

So, hopefully you could see that this is larger than the one we were just looking at, and that we would put three of those squares down the side and we'd be able to fit six across the top.

If we counted, all of those, we'd get 18, but we can actually do some multiplication instead, because we could do three, lots of six is 18.

So 18 units squared.

Okay.

Here's your task then your independent task for today's lesson.

So what you will need to do is find some flat surfaces in your house.

And then what you'll need to do is cut out a square piece of paper that are measures about a centimetre or two.

So ask a parent or carer to help you cut out carefully if you're using scissors.

So cut out a small piece of paper about a centimetre and use it to measure the area of your flat surfaces that you found.

What would be really good is different size books, a chopping board, anything flat.

Estimate firstly, how many squares do you think it would cover, would take to cover that whole area.

And then measure it.

So carefully, move your square and see how many squares cover the surface of your item that you found.

Don't pick something too big, 'cause you will be there all day working it's out.

You can then draw out a little graph, so you can do what your object is.

Your estimates, and your little square will be your unit squares.

So if you think 20 of them, so you could write 20 units and then you can put your little two above units, which means squared.

And then the actual size.

Good luck, finding your area of your shapes around your house.

Well done for today's work everybody.

Bye bye.