Lesson video

In progress...

I've had a little bit of free time waiting for the lesson to start.

One thing that I really like to do, if I have a spare moment is to look through some old photo albums. And while I was doing that earlier, I came across a photo from when I was in, I would say year four or there about, let me show you, what do you think? Have I changed very much since I was at primary school? I think I have quite a bit.

Right, I'm going to put the photo albums away so I can get focused and ready for this maths lesson.

If you need to move away from any distractions as well, then press pause in a moment and take yourself somewhere where you will be able to focus on your learning for the next 20 minutes.

Press pause now, and to come back when you are ready to start.

In this lesson we are developing strategies for planning and solving problems. We will start off with a matching measurements activity before spending some time exploring the problem, responding to the problem, and I will then leave you to solve the problem in the independent task.

Things you're going to need a pen or pencil some paper, the pad, or a book and a ruler.

Press pause, collect the items, come back and we will start.

Here we go.

Match the equivalent masses use the helpful hint.

One kilogramme is equal to, you say it.

1000 grammes and 1000 grammes is equal to, good, one kilogramme.

One's already been connected for you.

200 grammes is equal to 0.

2 kilogrammes, two tenths of a kilogramme, 20 hundreds of a kilogramme 200 thousandths of a kilogramme.

Press pause, match up the other masses, then come back and we'll take a look at the solutions.

Should we take a look? How did you get on? Can you hold up anything that you were writing down or drawing any copies of this that perhaps you made off on your own paper let me have a look.

Really good, let's check them off, shall we? So we have got 2000 grammes.

What if 1000 grammes is one kilogramme, 2000 grammes is two kilogrammes.

Next 1,500 grammes, one and a half kilogrammes, 500 is half of a thousand, so 1.

5, one and a half kilogrammes.

We of course, would be able to match that one up really quickly I am sure, a thousand grammes and one kilogramme.

Now we've not got a thousand grammes, we got a lot less than a thousand grammes, only 10 grammes.

That is ten thousandths 100, 0.

001 kilogramme.

Whereas 100 grammes more now more than 10, 100 grammes, 100 thousandths, 10 hundredths, one 10th, 0.

1 kilogramme and 1,550 grammes, more than 1,500 grammes so more than 1.

5 kilogrammes, 1.

55 kilogrammes, 550 thousandths, 55 hundreds 1.

55.

Let's now move on and take a look at the problem that is the focus of this session.

And it's actually all to do with mass.

It's called 2.

7.

Let's have a read of the problem together.

Rita has a selection of weights.

She selects 10 different weights.

However, there is one size of weight, which she does not use any of.

The total weight of them is 2.

7 kilogrammes.

The questions you're going to answer by the end of the session, which was the weight that she did not use? And how many of each weight did she use? To get us ready for answering those two questions independently, by the end of the lesson, let's slow things down and take a look at a few questions together.

First, how many weights has Rita got? Call out on three, one, two, three, good six.

You can see them right there.

She has six weights that she's able to choose from.

What is the total weight of them? What is the total weight of the six weights, that she has to choose from? Perhaps press pause, while you work that out, come back when you're ready to tell me.

So what's the total weight of them? So we've got 1000, 500, 100, 50, 20 and 10.

Where did the thousand come from? Ah, one kilogramme is equal to 1000.

And if we're calculating with units of measure, much more helpful, if those units are the same.

So I've converted one kilogramme, 1000 grammes.

I've combined one thousand with the 500 and 100, 1,600 plus 50 plus 20 plus 10.

1,680 grammes is the total weight of those six that she has, or the total mass of those six that she has to choose from.

How many weights has she got, which total 2.

7 kilogrammes? Is the answer six? No, let's look back at the problem.

Have you noticed how many weights? She selects 10 and the total mass of those 10 will be 2.

7 kilogrammes, okay.

How many different types of weights has she got? How many, say it again? Six that's what I'm thinking.

She's got six to choose from.

She will use 10 altogether, and we know that there is one of the six that she does not choose to use.

Which is heavier one kilogramme or 10 grammes? Remember my tip earlier when the units of measure are different, it's helpful to make them the same first.

You have a go come back when you think you can tell me.

So, which of them do you think is heavier? Okay and how could you convince me then? Because I might say to you, if you're saying one kilogramme is heavier, I might say, well, one is a smaller number than 10, so 10 grammes must be heavier.

What would you say to me? Good, if we convert one kilogramme to 1000 grammes, now I'm comparing 1000 and 10 of the same thing, grammes.

Clearly 1000 grammes is heavier than 10 grammes.

One kilogramme is heavier and we can convince anyone who's unsure by converting to 1000 grammes first 1000 grammes is greater than 500 grammes.

How many 500 gramme weights is the same as one kilogramme weight? Press pause if you need to.

You think you can tell me how many do you think? Two, and how can you convince me it's two five hundreds? Good, because one kilogramme is equal to 1000 grammes and two five hundreds is equal to 1000.

So two 500 gramme weights would be the same.

What is one kilogramme in grammes? You're going to be quick at this no pausing necessary.

Tell me on three, one, two, three.

Yes, 1000 grammes.

What is 500 grammes in kilogrammes? You might want to pause for this one.

Ready to tell me on three, one, two, three, good, 0.

5 kilogrammes.

It's half of a thousand, 500 hundred thousand is equal to five tenths of a kilogramme, 0.

5.

This one I definitely would like you to pause that.

What would the total weight be the total mass be, if she had each of those weights in the list? Press pause, work out their total mass, come back when you're ready to share.

Let's take a look.

So two one kilogramme weights, four 500 gramme weights, two 100 gramme weights, one 50 gramme weight, one 20 gramme weights and not any 10 gramme weights.

So what did you get as the total? Tell me on three, one, two, three.

I can hear some talking and kilogrammes, some in grammes.

Let's compare let's check.

So we've got two kilogrammes, we've got five, another two kilogrammes, so four kilogrammes, 270, 4.

27 kilogrammes, 4,270 grammes.

Now, when we think of that original problem, we're choosing 10 and here one, two, three, four, five, six, seven, eight, nine, 10.

We chose 10 there total was 4.

27 kilogrammes.

But for the problem to be solved, the total needs to be 2.

7 kilogrammes.

So we need to choose any 10, we need to not use one of them, and the total must be 2.

7.

So what would you say about our total here? It's too much, too heavy.

So we would need to make some changes for the next go that we have.

So it's important here to consider how we might record our results.

I've got to table to show you that you might like to use that I think would help you keep track of each of your do's each of your tries.

So on here you can see each of the weights we can choose from in that next line.

Two kilogrammes, four 500 grammes.

That's the goal we just had together.

And we can see yet red because we didn't use the 10 gramme weight and the total that we had there.

And the next line is another go.

So I tried earlier while I was getting the lesson ready.

And that time I didn't use the 500 gramme, but I used as you can see two kilogrammes, 200 grammes, one 50 gramme, one 20 gramme and four 10 gramme totaling 2,310 grammes or 2.

31 kilogrammes.

Either way t's too light.

It needs to be 2,700 grammes or 2.

7 kilogrammes.

So I've got space in my table to have another go.

And the table will help me to keep track of what I've tried, what I could try next and I'll be able to see how near or far I am from 2.

7 kilogrammes, 2,700 grammes.

Press pause and go and have a go at the problem.

There is a solution, even if it's starting to feel like there isn't because you keep on trying and you're not able to get close enough.

Persevere, look closely at what you've tried already, use that to make decisions on what to try next.

Think about what you're doing and you will reach the solution.

Okay, how did you get on? Can I see what you've been drawing or recording, anyone that used the table? Hold up, let me have a look.

Oh, fantastic, so well organised.

I can clearly see the weights you've used, the one you haven't used, the total mass of all 10 of them.

And I can see where that final solution was two.

Brilliant work everyone well done.

So this is the final solution the weights that we didn't use.

100 grammes and we used each of those others with the number of each weight represented.

The total there 2,700 grammes.

Give me a thumbs up.

If you enjoyed this session and working towards solving the problem.

Think about the decisions you're making, why you're making those decisions, think about the changes you're making after each of your terms, and what you're doing to help reach the solution.

Because that process, the learning is the most important part.

The solution is the result of the learning.

Keep a focus on that, on that process, and there may be parts that you can transfer from the process of today's problem into future ones.

If you would like to share any of your learning from this session with Oak National, please ask a parents or carer to share your work on Twitter, tagging @OakNational and #LearnwithOak.

Thank you for joining me for this lesson and successfully tackling the problem 2.

7.

I hope you enjoyed yourselves.

And I look forward to seeing you again for any future maths lessons, very soon.

Have a wonderful rest of the day with whatever you have lined up and see you soon, bye.