Lesson video

Hello my name is Miss Robinson.

I this lesson we're going to be finding half of different amounts within 10.

We're going to start, by finding half of an amount, and figuring out what that looks like, then we're going to check to make sure that things are equal.

Because in order for it to be half it must be equal.

Then it will be time for us to investigate some different halves, and then it will be time for your task, which is where you're going to do lots of investigating.

For this lesson you will need 10 things, you might like to have these near you, so that you can share along with me, but you will definitely need them for your task at the end.

And you will also need a part whole model, which you can draw on a piece of paper if you need.

Pause the video now to collect the resources that you need, and when you're ready press play.

When we think about finding half, its the inverse of doubling.

So instead of having two groups that are the same that we add together, we are getting a quantity, and we're splitting it into two equal groups.

I can see two different representations of half on the screen at the moment.

I can see a Ladybird that has two wings, both of which have two spots on them.

So all together she has four spots, that each wing has two spots.

So half of four is two.

I can see that those are two groups, so they are the same size that I've made out of my original whole of four.

I can also see some apples, that have been shared into two groups.

Each group has three.

All together there were six apples, we've shared them into two groups, half of six is three.

Can you repeat after me those two sentences, for the Ladybird half of four is two, and with the apples half of six is three.

Excellent.

We need to remember that to find half, we need to share into two equal groups.

If we can't share into two equal groups, we cannot half that number.

So I can see here, some apples in a part whole model.

I'm going to represent these apples using cubes, and I'm going to show you under the visualizer, me sharing the into two equal groups.

All together there are 10 apples.

So lets see if I can find half of 10.

So I've chosen to use characters instead to represent my apples, and I'm going to try to fit them all in my part whole model, So I needed 10 apples, So there we go ooh its a bit of a squeeze isn't it? Sorry, its a very little part whole model.

I've got three, six, nine and one more is 10.

All together there are 10 apples.

I wanted to see if I could find what half of 10 was.

So what I need to do is try and share them into these two equal groups.

Half means two equal groups.

So lets try.

One for you, one for you, can you join in with that sentence? One for you, one for you, one for you, one for you, one for you, one for you, one for you, one for you.

In the top part, I have one, two, three, four, five, and in the bottom part I have one, two, three, four, five.

So half of 10 is five.

If I hide this one, all am showing you is half of 10.

I know it's half because these are equal groups.

They are the same size.

So I've managed to chop my 10 in half.

Half of 10 is five, can you copy that sentence? Half of 10 is five.

It's time for you to investigate.

What I'd like you to do is work systematically, to investigate all of the numbers to 10.

And figure out which ones you can share, into two equal groups, and which ones you cannot share into two equal groups.

So that's which ones you can half, and which ones you cannot half.

On the screen is a table that says can share and cannot share.

So can half and cannot half.

What you need to do is use your part whole model, whether you've drawn it or you're going to use the one that is part of the task shapes, and you're going to share out your items into the two groups checking to make sure that they are equal, or if they are not equal putting them can't share column.

What you could then do is work systematically if you like, so starting with one and deciding if you can or can't share one.

Then, working with two and deciding if you can or can't share two.

Then working with three and then four, and then five, all the way until you get to 10.

So I'm going to show you me, starting to work systematically through the numbers to 10, and deciding whether I can share them, so can half them, or whether I cannot share them cannot half them.

So I'm going to start with the number one.

One for you, ooh ooh now there's none left.

So the number one cannot be shared, I cannot find half because half needs to have two equal groups.

Let's try the number two.

Here's two.

One for you, one for you, there's one in this part, and one in this part.

The number two can be shared.

I can half two.

Half of two is one.

Let's try three, one for you, one for you, one for you.

Hmm, what do you think? Can I share? Hmm, what do you think can I find half of three? Are the two groups equal? No, I cannot find half of three, I cannot share it into two equal groups.

This one has two, this one has one, they're not the same.

So I cannot find the half of three.

Now it's time for you to pause the video, and complete your task.

Remembering that you are sharing into two groups, and then checking to see if those two groups are equal.

If they are equal, then we can find half of that number, if they're not equal then we can't.

Pause the video now to complete your task.

When you're finished press play.

So what did you find out? I found some interesting patterns, and I also found, something that linked halving to doubling.

Here is my table, remember on the can share column, those are the numbers that I could half, because I could find two equal groups.

On the can't share column, the cannot share, that's the numbers that I could not half, because I could not split them into two equal groups.

First, can you see the pattern that I spotted? You might need to look down the two columns to see the pattern.

Both columns are jumping in two's, the first column, is like how we count in two's, two, four, six, eight, ten.

The second column is like we're counting in two's if we started at one.

One, three, five, seven, nine.

Each column has every second number.

So actually if I start in the cannot share column, and I jump back to the can share column it's like I'm just counting normally.

So I'll go one, two, three, four, five, six, seven, eight, nine, 10.

I can also see that all the numbers in the can share column, are even numbers.

And all of the numbers in the cannot share column are odd numbers.

I also used my knowledge of doubling to check my answers.

So when I started with the number four, I had four cubes, and I split them into two equal groups.

So that is why the number four is in my can share column because I could find half.

I could find two equal groups.

But I also knew that double two was four, I could check my answers by using my knowledge of doubles.

Did you find anything interesting? Are any of your numbers in different columns to my numbers? If they are you might want to pause the video now, and go back to sharing in and check.

Thank you for joining me today, I hope you've enjoyed sharing and finding half, as much as I have.

Why not share your work with us? If you'd like to, please ask your parent or carer, to share your work on Twitter by tagging @OakNational and using the #LearnwithOak, we'd love to see what you've been getting up to.

Don't forget to go and complete the quiz! Thanks again for joining me.

See you next time.