# Lesson video

In progress...

Hey guys, can you believe it.

This is our final lesson, okay? Sorry I'm running around the lot today because I've got a surprise for you all.

I'm organising a party in the beach to celebrate the great work we've done in this whole unit of measures, okay? But the thing is, unfortunately, I've left things in the last minute.

So I need help organising with what we need to bring and what we need to measure.

Okay, and I know that I'm dealing with the right people here because you guys are fantastic mathematicians when it comes to measurements.

So let me show you what we're doing today, okay? Right, so first we need to work out how much we need to bring.

Then we need to know how much we already have.

So how much is already there, then we're going to be measuring and estimating, so we make sure we have the right amount, okay? And then I need to go and set up so then you guys are going to get on with the independent tasks and complete the rest of the organisation for me.

And I'll be back just in time so we can go over the answers together.

So we have the best party to celebrate the great work you've done.

So you're going to need a pencil in the ruler, a rubber and an exercise book to complete these tasks.

So let's get started.

So you guys need to make squash for the party.

Now to make one cup of squash you need 25 millilitres of juice and 200 millilitres of water.

Now, I need to buy the juice and water because unfortunately there's no taps on a beach.

So you need to work out how much juice and water I need to get.

Now, there will be eight people with us all together in the party.

So if everyone gets one cup of juice, how much juice and how much water will I need to buy? And that's what we're going to figure out today.

Okay, so I know that one squash is 25 millilitres of juice and 200 millilitres of water.

So what I'm going to do is I will be working out the juice and then you guys can work out the water.

So let's work out the juice first.

So if I know that one cup is 25 millilitres of juice, that means that one part is equal to 25 millilitres and I know there's eight of us, so I know that there's eight equal parts.

So what we're tryna find out is our whole.

So then our bar model is going to look something like this.

Now, I need to work out the calculation.

Well, when it comes to multiplication division, if I'm trying to find a whole, then I need to multiply the number of equal parts, which is eight.

One two three four five six, seven, eight people by the amount of one part, okay? Which is 25 millilitres so our calculation is 25 millilitres times by eight.

Therefore our answer is 25, 50, 75, 100, 125, 150, 175, 200 millilitres.

Now the bar model was used to help me do this, okay? So when it comes to your turn, I'd like you to draw your bar model too.

Okay, so guys, I need you to figure out how much water we need.

I'm going to quickly go and continue in setting up till we're ready.

So pause the video and then come back and we'll go over it together.

Okay, pause it.

Running around today.

Okay so, how much water do we need? The answer should have been, one litre and 600 millilitres.

Okay, how do I know this is correct? Well, if I know there was 200 millilitres of water, then your bar model should've looked like this.

Okay, very similar to the last one where we have eight equal parts and one part is 200 millilitres so therefore our calculation should have been eight times 200.

Well, if I know that eight times two is equal to 16, then eight times 200 is equal to 1,600 millilitres, but we need to give the answer in mixed units, okay? So 1,600 millilitres in litres and millilitres would be one litre and 600 millilitres.

Well done guys.

Thanks so much for your help.

Oh no, I've just realised it's actually quite warm outside and maybe one cup of squash might not be enough.

Do you know what? I'm really sorry.

I think we're going to have to need at least two cups each.

Okay so, right.

You know, I like to be prepared.

So I want everyone to have at least one cup of water.

So everyone will be able to have twice as much juice, okay? So now, how much do I need to buy if I know that I need twice as much of everything, okay? So what I'm going to do is if I know that the water is one litre and 600 millilitres and the juice we worked out is 200 millilitres.

I'm going to work out how much juice we need and you're going to work out the water, okay? And I think that's fair.

All right, so let me figure this out then.

If I know that one part is 200 millilitres and I know that it's twice as much.

So I need to times that by two and therefore we're trying to find our whole, so our bar model should look like this, okay? Where we have 200 millilitres as our parts, we know we need twice as much and our whole is what we're trying to find out.

So our calculation here will be-- Well, I know that when we are multiplying and dividing, when we don't know our whole, we need to multiply our part, our one part by, in this case, two, okay? By how many equal parts there're.

So, our calculation will be 200 millilitres times by two.

Well, if I know two times two is equal to four, then 200 millilitres times by two is equal to, 400 millilitres.

I need to quickly go off and continue setting up.

Can you please find out how much water we need, okay? Remember that we have one litre and 600 millilitres of water ready and we need twice as much.

Okay, so pause the video and I'll be right back, go.

Honestly, burning a lot currency.

Okay, so let's find out what the answer is.

Our answer is, three litres and 200 millilitres.

Now, your bar model should look like this, okay? Where we know that one part is one litre and 600 millilitres.

We know that it's twice as much and the unknown is the whole.

And remember when we're trying to find our whole, when we're multiplying and dividing, we need to multiply the one part by the number of equal parts, in this case, two.

Times by two.

Guys, you've been so helpful so far.

Thank you so much.

Okay, so how much is there ready? So there's a bag of fruits containing bananas and satsumas and the bag weighs one kilogramme and 500 grammes.

Now, let's assume it, weigh 800 grammes, but I want to know how much the bananas weigh, all right? So what I'm going to do is I'm going to use a bar model.

Of course I am.

Well, what do I know? Well, I know that the whole of the total is one kilogramme and 500 grammes and I know that one of my parts is 800 grammes.

Is there two parts within my whole? I think so, absolutely because we're not comparing two different things.

It's the same bag.

So this should be the bar model that you're drawing, okay? Where we have our whole as one kilogramme of 500 grammes and one of our parts is 800 grammes.

And two parts within the whole, okay? You're not comparing.

Right, so what is that calculation? Well, I know that when we're adding and subtracting, when we're trying to find out a part, we need to do whole takeaway part.

So in that case, our calculation is one kilogramme and 500 grammes take with 800 grammes.

Right, we're about do something we haven't done before, okay? So as you can see, our problem here is 500 takeaway 800.

We can't do that calculation.

So what am I going to do? Well, this is what we're going to do.

We're going to change one kilogrammes into grammes.

Because I know one kilogramme is equal to 1000 grammes, okay? So therefore I can say that one kilogramme and 500 grammes is the same as 1,500 grammes.

The reason why I am doing this guys is because now I can takeaway 800 grammes because remember we can't takeaway numbers with different units.

So now that I do 1,500 takeaway 800 grammes, I get 700 grammes, which will give me my answer.

So the way to the bananas, 700 grammes.

That's really good.

Okay, so-- Oh no, guys I'm so sorry I've done it again.

I just realised that I've also got grapes here.

What am I like? So turns out that I actually bought an extra one kilogramme and 600 grammes of grapes.

So now I need to work out the total mass of all the fruit now and I need you to give your answers in mixed units.

I'm so sorry, I would do it with you, but I need to go set up all of the-- I don't want to tell you about the surprises of the party, okay? So what are you going to do now is, is you're going to pause the video and calculate the total mass of all the fruits in the bag.

Okay, okay, off you go.

Okay, I'm back.

Okay right, so the answer should have been? Three kilogrammes and 100 grammes.

Okay, really good and hopefully you use your bar model to do this and your bar model should look like this, where we have two parts which create one whole, because that's what we're tryna find out.

The total mass of all of our fruits, right? So one part was one kilogramme and 600 grammes and one part was one kilogramme and 500 grammes.

And to make a whole we need to do two parts plus part makes a whole and we know that part plus part makes a whole.

Well done, guys, let's go to next question.

So I went to the store-- Okay, and I need help reading the scales because I love biscuits, but the thing is, I need to be careful because my bag could only hold one kilogramme and 900 grammes.

So I find this box of biscuits and I'm not sure if it's going to be too heavy for it.

So you're going to help me read the scale so we can find out the weight of these biscuits.

All right, okay, we're going back to what we know.

So let's ask ourselves these questions.

What is the scale? What is the value of each interval? What two intervals is it in between? Which intervals is the mass closer to? And then we're going to make our estimation.

Okay, so what is our scale? And that is kilogrammes and grammes.

Okay, really good, so we have a mixed units in there.

So what is the value of each interval? So let's have a look then.

I'm going to look from zero to 500, okay? That's what I want to look in between.

I'm want to count up how many intervals is in there.

One, two, three, four, five.

Okay, there's five intervals of the value of 500 grammes.

Let me think, maybe 50, let's try 50.

50, 100, 150, 200, 250.

Ah, not quiet.

Well, 250 is half of 500.

So maybe I might try 100.

Let's try that 100, 200, 300, 400, 500.

That's it, so the value of each interval is 100 grammes.

So what two intervals is our indicator in between? So let's have a look.

It is in between-- Well, so 600, 700, 800, 900 and 1 kilogrammes.

So it's between 900 grammes and one kilogrammes.

Which interval is the mass closer to? So it looks like it's a lot closer to 900.

In fact, it's almost on 900.

So therefore my estimation is going to be about 910 grammes, okay? Okay, so it looks like I've got quite a lot of space, you know what? Oh guys, I just found a bigger box of biscuits.

I'm so sorry to be a pain today, but can you please, can you please measure this one for me.

I need to go off and do something and then we can see.

Hopefully that can fit into our bag because we've got so much space in our bag, we might as well fill it, right? So here is, I'm going to quickly go sort out the party.

Just pause the video and just tell me how much that this big box of biscuits ways, okay? Hopefully it's less than one kilogrammes and 900 grammes.

Okay, I'll be right back.

Okay, right.

Hopefully, hopefully it's not too big.

So this bigger box should weigh already.

One kilogramme and 390 grammes.

Okay, so let's have a look.

Well, our scale is in kilogrammes and grammes.

Our interval when it looks like as the same as before, 100 grammes, it's count from one kilogramme.

One kilogramme and 100 grammes, 200 grammes, 300 grammes, 400 grammes.

So it's in between one kilogramme and 300 grammes and, one kilogramme and 400 grammes.

It's closer to one kilogramme of 400 grammes though, isn't it? It's actually almost on there, which is why I've gone for one kilogramme 390 grammes, okay? Thank you guys, I know I'm being a bit of a pain today.

Well done.

Okay, so I don't know if it's because I was running around, but the heat today is very strong, okay? So I've decided that I need to bring an extra jug of water to keep us safe.

Now this is my job.

I'm not sure if this is enough, but what we're going to do is we're going to measure this jug and I think this might be enough for us to take for eight people.

So let's find out.

Okay, so what do we need to do? So what is the scale? What is the value of each interval? What two intervals is it in between? Which interval is the capacity closer to? And then we need to make an estimation.

So what is the scale, millilitres really good.

What is the value of each interval? Well, the value of each interval, well we need to work this one out.

Let's have a look from zero to a hundred then there is one, two, three, four intervals, okay.

Well, if half of a hundred is 50, then this is 50.

And half of 50 is, it's 25.

That means that each interval should be equal to 25 millilitres.

So then what two intervals is in between.

All right, well, if this is a hundred, this is 125, 150, 175.

So its in between 150 and 175 millilitres.

Which intervals the capacity closer to? Well, it seems like it's closer to 150.

So my estimate is going to be about 160 millilitres in a container, okay? Okay, really good.

So, somebody tells me that, "I don't think that's enough water." Do you know what, I'm going to get a lot more, but I know I'm really sorry, guys.

You're going to have to do this again.

This is my other container.

I filled it with a lot more water because I feel that we're going to need it.

I'm going to continue organising our party, pause the video and I'll be back to see how much is in this water.

Okay pause, good luck.

Okay, to be honest, Imma feel I'm going to need all of this water, just from all this running around I'm doing.

So let's find out what our answer is.

So our answer should be, 650 millilitres.

Let's find out, okay? So we know that the units are millilitres.

We going to need to work out the interval.

Okay so, this is a lot more intervals in this one.

So let's figure this one out.

So there's one, two, three, four, five, six, seven, eight, nine, 10 intervals from zero to 500.

Okay, well, if I know that 10 times five equals 50, then I know that 10 times 50 will equal 500.

So I think it might be 50 guys.

Let's try 50, 100, 150, 200, 250, 300, 350, 400, 450, 500.

Yes, we've got the interval.

Therefore we can count from here, 500, 550 600, 650.

Okay guys, it's time for the independent task.

Now let's do a couple exercises to do while I go off and organise the party.

And I hope that you guys follow all of those steps, okay? Remember to think about everything we've learned in this unit.

Be confident in what you are doing.

Pause the video, go to your worksheets, complete the task, then come back and we can go over the answers together.

Good luck guys and thank you for your help.

Okay, right, time for our answers.

So, for people have arrived to the party, you need to make squash for them, okay? So to make one cup of squash, you need 40 millilitres of juice and 250 millilitres of water.

Now I need to buy the juice and the water because remember there's no taps in the beach.

So you need to work out how much juice and water I need to get.

So if everybody needs one cup of juice, how much juice and water do I need to buy? So I'm going to work out the juice first.

Well, if I know that one part is 40 millilitres and I know that I have four equal parts then my bar model should look like this, okay? And in this calculation, when we are multiplying and dividing, if we don't know the whole, then we need to multiply the one part by the number of equal parts.

So that's 40 times by four, which gives us 160 millilitres.

Okay, now it's time to work out the amount of juice.

So it's 250 millilitres is one part and we have four equal parts.

So very similar to the last bar model, it should look like this.

So then our calculation is, remember if we need to work out the whole, it is the number of equal parts multiplied by one part by the value of one part and that should be 250 millilitres times by four, which is equal to 1000 millilitres.

Wait a minute, 1000 millilitres.

What does that equal to? One litre.

Well done guys, let's go to the next one.

I split the party into three groups, okay? Because this is a lot to organise.

Now, I have three litres and 900 millilitres of a drink.

Now, to avoid any arguments, I've decided to share the drink equally between the groups.

So how much drink does each group get, all right? So what do we need to do here? So this is a water problem.

What do I know? Okay, so I know that my whole is three litres and 900 millilitres of drink and I know that I have three equal parts because it's three groups.

So your bar model should look like this.

So this is our three groups and this is our whole and this is what we need to find out, okay? So remember our calculation here.

If we're tryna find a part, then we need to divide the whole by the number of equal parts.

So in this case, it'll be three litres and 900 millilitres divided by three.

So remember that we need to group like terms and we need to divide them separately.

So then it will be three litres divided by three, which is equal to one litre and 900 millilitres divided by three, which is equal to 300 millilitres.

I know that because nine divided by three is equal to three.

Therefore 900 divided by three is equal to 300 millilitres.

Our answer therefore should be one litre and 300 millilitres.

Thanks guys.

Now, we've come to the end of the party.

It's been great, okay? Now, I have a bag that weighs one kilogramme and a hundred grammes with all my sweets and my snacks inside.

Now, after a fun-filled party, I noticed that the bag is almost empty.

Oh wow, that's a lot of sweets.

No wonder all the children were running around crazy on a sugar rush.

So we needed to work out what was the mass of the bag, right? But what is the scale? The scale is kilogrammes and grammes.

I know the value of each interval is 100 grammes.

And what two intervals are in between? Well in this case, it isn't in between any interval its exactly on one kilogramme and 500 grammes.

The second part of the question says, "What was the mass of the sweets and the snacks "that was eaten by the children?" All right, so bar model time, okay? So I'm comparing two numbers now.

So I know that my whole is one kilogramme and a hundred grammes and one of my parts is one kilogramme and 500 grammes.

So, I need to draw this bar model right here, okay? Now, to find out this part, remember when we're finding out parts, we need to do whole takeaway part.

So this should be our calculation and then we need to group all like terms. So it'd be one kilogramme takeaway one kilogramme, which is zero kilogrammes, which is zero.

And then we have 900 grammes takeaway 500 grammes, which is equal to 400 grammes.

So I'm left with 4-- I'm left with 400 grammes of snacks and sweets.

Oh, I thought I have way more than that.

Well, nice you guys had a good time, but let's go into the next question.

Okay, so at the end of the party, I want to see how much drink is left as well.

So I decided to place it into a measurement cylinder.

What is the capacity of the container now? So I need your help guys.

So what do we do? What is the scale? What is millilitres, okay? What is the value of each interval? Well, let's find out one, two, three, four, five.

Okay, so there's five intervals from zero to 500.

Okay, so then each interval is going to be equal to 100 millilitres and which two intervals is it in between? And very similar to the last one, it's not really in between, it's exactly.

Well let's count it, 600, 700, 800 millilitres.

The second part it says, well, I realise that I had five times that amount of drink at the start of the party.

So how much drink did I have at the start of the party? So I know I need to do a bar model here.

So if I know that one part is equal to 800 millilitres and it was five times bigger at the start of the party, then I'm going to draw a bar model just like this, okay? Well, we're tryna find our whole.

So remember, when we are dealing with multiplication and division and we're tryna find our whole, we need to multiply the one part by the number of equal parts, which in this case is five.

So 800 millimetres times by five, which is equal to 4,000 millilitres.

Now, I know that 1000 millilitres to one litre, therefore 4,000 millilitres is equal to four litres.

So that's how much I had at the start of the party.

All right, guys, it has been an absolute, wonderful journey that we've been on during this unit.

I hope you guys have learned so much and you've had fun along the way, as much as I have.

I hope that you remember each part and all the steps that we take when we're measuring mass or volume and how we use our bar models and hopefully you guys will become experts using them in the future.

Wish you all the luck for the rest of your learning today and hopefully see you guys soon, bye.