# Lesson video

In progress...

Hello, and welcome to this lesson about reading weighing scales with different intervals.

My name is Mr. Nieto and I'm currently a year four teacher.

This is my first lesson of many, and I hope you are as excited as I am to go on this journey together.

Please take a moment now to clear away any distractions, including turning off the notifications on any apps or conversations you have running if you know how to.

Finally, if you can, try to find a quiet place where you won't be disturbed during the lesson.

Okay, so when you're ready, let's begin.

Let's begin with the lesson agenda.

First, we will be identifying the value of intervals on a scale.

Second, we're going to be rounding mass to the nearest interval.

Third, I hope that you'll be confident enough to continue with your independent task.

So, you will need a pencil, a rubber and an exercise book to do all your incredible learning.

So where have you seen weighing happening? You have one minute to find as many examples as possible of items in your house where weighing is happening.

Now, before you go, make sure you pause the video.

I found weighing scales that weigh my weights every morning.

And I found weighing scales that helped me make some incredible cakes for my family, What did you find? What weighing have you done? I'm sure that lots of you may have weighed yourself on some weighing scales.

Maybe you've helped your parents make some incredible cakes, and you've had to use weighing scales for that, or maybe when you've gone to the market, you've had to weigh some fruits, some veg, and to see how much it costs.

My next question is, what units have you seen? There's a mixture of kilogrammes, grammes, millilitres, and litres.

Today, we are going to be focusing on kilogrammes and grammes.

So when we're thinking about mass, you need to know that one kilogramme is equal to 1,000 grammes.

That means, two kilogrammes is equal to 2,000 grammes.

And three kilogrammes is equal to 3,000 grammes.

And four kilogrammes is equal to 4,000 grammes.

And 13 kilogrammes is equal to 13,000 grammes.

And it goes all the way as well.

So, 1,000 grammes is equal to one kilogramme.

2,000 grammes is equal to two kilogrammes.

13,000 grammes is equal to 13 kilogrammes.

And the difference is weights is massive.

Just to have a look here, a one kilogramme weight compared to one gramme, which is equivalent to a little paperclip, which as you know, is very, very light.

It's important for us to know that when we are trying to compare weights.

So when we are weighing things, we would normally use a weighing scale.

And on that weighing scale, we would find a scale.

Now, remember that a scale is a set of numbers that are equally spaced out.

Here, we have example of three weighing scales.

And in those weighing scales, we can see intervals.

And in the first one up here on the top, it has one interval, okay? And that value of the interval is one kilogramme.

The red arrow right here, that's what you call the indicator.

And that tells us exactly the mass of the object.

In the second scale, we have one, two intervals.

That means that the value of each interval is going to be 500 grammes.

And on the bottom scale right there, we have one, two, three, four intervals, which means the value of each interval is going to be 250 grammes.

And how we work that out is what we're going to be learning today.

So now, we're going to be identifying the value of intervals on a scale.

So what are we going to do is, we're going to follow these steps.

The first thing we're going to to say is, how many intervals can we see? In this top scale right here, we can see, one, and two intervals.

Then we look at the mass of the scale, the total mass, and that is 1,000 grammes.

Then we need to see, right, where is the interval? And it's halfway between.

So therefore, I need to know that half of 1,000 grammes or one kilogramme is equal to? 500 grammes.

Good, let's move on to this scale.

Next, what do we do first? What's the number of intervals? Exactly.

This one has four intervals.

Then we look at the mass of the scale, which is one kilogrammes or 1,000 grammes.

And then we need to think about what each value is.

So, I know that half of 1,000 is 500 grammes and in order to work out what one interval is, I then need to half it again.

So half of 500 is equal to 250 grammes.

Perfect.

I'm using the maths that I know to help me answer this question.

The final one, slightly tricky one, what do I do first? That's right.

Number of intervals is five.

The mass of the scale, the total mass is of 500 grammes.

And this time what I'm going to do is, is I'm going to use something that I feel comfortable with and that's my five times tables.

So let's do that now.

We're going to do them together.

Five, 10, 15, 20, 25, 30, 35, 40, 45, 50, 65.

And I could keep on going.

But, the reason I'm using that is because I know using my five times tables, that five times 10 is equal to 50.

Therefore, using my number facts, five times 100 is equal to 500.

Therefore, five 100s go into 500 grammes.

So one of my intervals is equal to 100 grammes.

Now that we've done that together, I want you to really help me out with the next one.

Okay, so the first one here, it's done for you, just to remind yourself, 'cause remember, the first thing we do is look for the number of intervals, which in this case is two.

And then, because we know it's half way, we do half of two kilogrammes this time, which is equal to one kilogramme or 1000 grammes.

Let's do the second one together.

Okay, so what do we need to do first? That's right, it's the number of intervals.

In this case, it is four intervals.

What do I do next? Well, I need to work out with what the total amount of the masses on the scale, which is two kilogrammes.

And I need to work at each individual interval.

The first thing I'm going to do is half of two kilogrammes or 2,000 grammes, which is 1,000 grammes.

Then, what do I need to do to work out this bit right here? That's right.

Half of 1,000 grammes.

So half of 1,000 grammes is equal to 500 grammes, which means each individual interval is 500 grammes.

Should we try it? Let's see, 500, 1,000, 1,500, 2,000 grammes, or two kilogrammes.

Perfect.

Now, we're going to move on to the final one.

First thing I need to do is? Number of intervals, which in this case is five.

Now, I'm going to use my five times tables.

So let's do that together.

Are you ready? Five, 10, 15, 20, 25.

Why have I stopped at 25? Yes, because we have 250 grammes.

So I can actually go, instead of five, 10, I can go 50, 100, 150, 200, and 250 grammes.

Therefore, using my times tables, or therefore using my five times tables, I can work out that each interval has the value of 50 grammes.

Right.

Now, I want you to pause the video and have a go at this question right here.

What is the value for each interval in the following scale? Pause the video and answer in your exercise book, and then unpause it to find the answer.

So let's find out how we did, the answer was, drum roll, 10 grammes.

Let's find out how we did it with our answer.

Now, first step, is to find out the? Number of intervals.

Which in this case, is five.

Then I'm going to use my five times tables.

Are we ready? Five, 10, 15, 20, 25, 30, 35, 40, 45, 50.

How many times does five go into 50? 10 times.

That means that there are five 10s in 50.

Therefore, each interval is equal to? 10.

Oh, don't forget the units, 10 grammes.

Right.

Onto the next part, rounding mass to the nearest interval.

Sometimes, we have got scales that have got a large amount of numbers.

And therefore, can be really difficult to read if the indicator is somewhere in between, just like this one here.

So what we need to do is, is sometimes we need to do a good estimation, okay? So in order to do that, we're going to follow five steps.

The first one is, what is the scale? What that means is, is what is the unit? And in this case, the scale is? Grammes.

Number two, what two intervals is it in between? Well, having a look at our indicator, you can see that they are in between 900 grammes and 1,000 grammes.

Good.

Number three, which interval is it closer to? Well, I can see that halfway is about here, and therefore is more than halfway, so it is closer to? 1,000 grammes.

Number four, this is the bit when we make an estimation.

So, I look at my scale and I see that it is more than, well, halfway between 900 and 1,000 is 950.

And it's about halfway between 950 and 1,000.

So I'm going to estimate about 980 grammes.

This is the language we're going to use.

The mass is around 980 grammes.

We're going to try that one more time.

The mass is around 980 grammes.

Around is the key word there.

Let's try another one.

Right, so let's have a look at this jar.

First step, the scale is measured in? Grammes.

Good.

Second step, the indicator is between? Let's have a look, 300 grammes and 400 grammes.

Perfect.

The indicator is closer to? 400 grammes.

And then, I have to do my estimation.

Well, this time I can, I have an extra interval right there, so that can help me out.

And that means that halfway between 300 and 400, is 350 grammes.

I know that because we learned that earlier today.

And I know that that's more than 350 grammes.

Therefore, I'm going to say about 390 grammes.

That is my estimation.

What do we say at the end? The mass of the jar is around 390 grammes.

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

This time, I need your help.

Okay, so here we go.

First step, we need to know the scale.

So, the scale is measured to? I look at my units there, and it is? Kilogrammes, perfect, right.

Second step, what is the indicator, or where is the indicator in between? Well, let's have a look at my indicator, and it's pointed in between 30 kilogrammes and 40 kilogrammes.

So it should be just like that.

Number three, which one is it closer to? Well, I can see that the indicator is far close to the 40 kilogrammes, and I'm going to put it there.

Here comes my estimation.

Again, using the skills that we learned before.

Well, I know that from 30 to 40 kilogrammes, we have one, two, three, four, five intervals, okay? And in between this, it is 10.

So I'm going to use my five times tables.

Are you ready to get to 10? Five, 10, two.

That means that each value of interval is two.

Should we make sure, should we check and find out? 32, 34, 36, 38, 40.

Well done.

Now, I'm going to use that to help me.

So if this is 36, and this is 38, it's sort of in between, so I'm going to go for 37 kilogrammes.

And don't forget the final sentence, the mass of the jar is, 37 kilogrammes? No, you're right.

I need to say, is around 37 kilogrammes.

It's time to try one by yourself.

So, you're going to pause the video at this point and read the question.

Estimate the mass of Larry the lizard.

Pause the video and try it for yourself.

Okay, so let's see how we did.

Boom.

Let's find out how we did.

Here we go.

So number one, the first thing we need to do is, what is the scale? The scale is grammes, okay? It is measured in grammes.

Number two, the indicator is between 400 grammes and 450 grammes.

Number three, the indicator is closer to 400 grammes.

Now, we go for estimation, looking at what we have learned before.

Well, from 400 to 450, that's 50 grammes.

And I know that this is halfway between there.

Therefore, half or 50 is 25.

So this line right there is, represents 425.

And that's a little bit below it.

Therefore, my estimation will be 420 grammes.

On my final sentence, the mass of Larry, or Larry the lizard is around 420 grammes.

So aside from my independent task, and as you can see from the emoji up here, I need your help, okay? You need to help me weigh parcels correctly at the warehouse that I'm working at.

Now, this is really important guys, because if I get this wrong, I'm going to get in trouble, and please, please don't get me into trouble.

In fact, I know you're going to help me, so I know I'm in the right hands.

So you need to calculate the value of the intervals and write the correct mass with the correct units.

So what you're going to do now is, is that you're going to pause the video and you're going to go to the worksheets and complete the task.

And when you're finished, come back here and we will go over the answer.

I know you guys are going to be amazing.

Good luck.

Okay, guys, thank you so much for your help.

And remember, if you've made a mistake, just correct it with a different kind of a pen if you can.

Here we go.

Parcel A.

First step, the scale is measured in? That's it, grammes, good.

Second step, the indicator is in between? 250 and 300 grammes.

Really good.

Number three, the indicator is closer to? Yep, 250 grammes, well done.

Now, thinking about how I work out my intervals, I'm now going to see that between 250 grammes and 300 grammes, it is 50 grammes, and this line is halfway between, and half of 50 grammes is 25 grammes.

Therefore, this line, it will represent 275 grammes.

So now, I'm going to use that to help me with my estimate.

That means it's between 250 and 275 grammes.

I'm going to go for 270 grammes.

Now, if your guess is between 265 to 273, I'd say that's correct.

Anything less or more, I think that maybe you need to have a look and have a better estimates, okay? It's okay, it's tricky.

If you've got, if you've made a mistake here, then we learn from them, okay? That's the points of mistakes.

Don't forget the final sentence, the mass of the parcel is around 270 grammes, or whatever mass that you decided to go for.

Well done guys.

So far, tick, that's one parcel out of the way in the warehouse.

So let's move on to the next one.

The parcel B.

First step, the scale is measured in? That's right, kilogrammes.

Second step, the indicator, is it between, let's have a look, 200 grammes and, oh, 200 kilogrammes and 300 kilogrammes.

Well done.

The indicator is closer to? 200 kilogrammes, good.

Now, it's time for my estimation.

Well, I know that between 200 kilogrammes and 300 kilogrammes, this value here is equal to 100 kilogrammes, and half of 100 kilogrammes is 50 kilogrammes.

So, this little green line here must equal 250 kilogrammes.

So now, I need to make my estimate.

Having a look, let's have a see, I'm going to go for 220 kilogrammes.

Now, I'd say, I'll take any answers between 210 kilogrammes to 225, 230 kilogrammes.

Anything more than that, I'd say, 240 would be closer to here, right? Like I said, if you make a mistakes, this is tricky, be patient.

We get through this together, okay? We learn from our mistakes.

And don't forget the final sentence, the mass of the parcel is around 220 kilogrammes.

Give yourselves another tick if you've got that correct or mark that right now.

So if it doesn't look like mine, change it now.

Onto the next one guys.

Right, parcel C.

The scale is measured in? Let's have a look.

Well, this is a bit tricky, because actually, I have grammes on this side, and I have kilogrammes on this side.

So, I know that this is then going to be measured in grammes because this can't be 100 kilogrammes, because this is one kilogramme.

So this is going to be 100 grammes, 200 grammes, 300 grammes.

So the scale is measured in? Grammes.

The indicator is in between? Let's have a look, 900 grammes and one kilogramme, or 1,000 grammes, okay? The indicator is closer to? Wow, well, that's quite nice and easy.

That's close to 900 grammes.

So it's time for our estimate.

Let's have a look.

Well, it lies in, the indicator lies in between 900 grammes or 1,000 grammes.

And I know that this has, one, two, three, four, five intervals.

So I need a number that goes up from 900 to 1,000, it's in five intervals, equally spaced.

Well, let me see, I only think of a five times tables.

I'm going to go with five, 10.

Hmm, I think that might help me because it's 100 grammes in between.

And if I know that five times two is equal to 10, then five times 20 is equal to 100.

So maybe it's 20.

Should we check? Let's find out.

920, 940, 960, 980, 1,000.

Great, that worked.

So I know that this is in between 900 and 920.

It's quite close in there.

So I'm going to go for 920 grammes.

That's my estimate.

Now, again, anything between 910 and 920, I think is correct because it's closer to 920 grammes.

Don't forget the final sentence, the mass of the parcel is around 920 grammes.

Let's go to the next one guys.

We're getting there.

Well done.

Okay, first step, the scale is measured in? Grammes, really good.

The indicator is in between 350 grammes and 400 grammes.

The indicator is closer to? Yep, 350 grammes.

Now, the estimate.

Well, I know between 350 grammes and 400 is equal to 50 grammes.

Half of 50 is? 25 grammes.

Good, we're getting the hang of it.

And you realise the more we're using these numbers, the better we become.

Practise makes permanent, they say.

Now, I need to do my estimate.

Therefore, this is 375 grammes.

So it's just underneath, and I'm going to go for 370 grammes.

So, the mass of the parcel is around 370 grammes.

All right, guys, we're almost there.

You guys are really helping me out.

Let's go to this one, the final one.

Okay, first step, the measure, the scale is measured in? Oh, and this time, we don't have a unit here, but we do have it there.

So therefore, it is kilogrammes.

Then the indicator is in between 100 kilogrammes and 200 kilogrammes.

The indicator is closer to, I'd say, well, this is about half way, and it's close to 100 kilogrammes.

Now, the estimate.

Well, let me see how many intervals are in between, one, two, three, four.

And from 100 to 200, is 100 kilogrammes.

Well, what's half of 100? That's 50, so this is 150.

And what's half of 50? 25.

So this is 125.

So each interval is 25.

So it'd be at 100, 125, 150, 175, 200.

And I can see my indicator is in between 125 and 150, but it's closer to 150.

So I'm going to go with 140.

It's going to be my estimate.

I'd say, I would take any answers on the ranges of 135 to 145, okay? 'Cause it's not quite 150 just yet.

And the mass of the parcel is around 140 kilogrammes.

That brings us to the end of today's lesson.

A really big well done on all the fantastic learning you've achieved today.

I've got two final things I'd like you to do now.

First, if you're able to, please take a picture of your work and ask your parent or carer to share it with your teacher so they can see all the fantastic things you've learned today.

And if you'd like, ask your parent or carer to send a picture of your work to @OakNational on Twitter so I can see your lovely work too.

Second, complete the quiz to see what you have learned today.

Well, all that's left for me to say is, thank you, take care, and enjoy the rest of your learning for today, ciao.