Lesson video

Hello everybody, my name is Miss Hughes and welcome to today's math session.

In today's lesson, our objective is going to be using number bonds to 20 to help us with addition.

And we're going to be using our known number bonds to 10 to help us with this.

So let's get started.

Let's have a look at our lesson agenda for today then.

We are going to start off with looking at number bonds within 10.

Then you're going to have a go at a spinner game, next, we're going to look at number bonds within 20 and finally you will have a main task and a quiz.

For today's lesson, you are going to need a pencil and a rubber, some paper and you are also going to need a spinner and the paper clip.

You can draw the spinner out yourself or if you don't feel confident drawing out yourself, there is a printable resource or principal spender that you can download and print off to use.

Pause the video now to get these things if you have not got them already.

We're going to start off our lesson today with some number bonds.

So we need to have a look at the part whole model on all of the part whole models that are on this slide.

And I want you to shout out what the whole in each of these part whole models is.

So let's go through them.

My two parts are one and one, so my whole is, two.

My parts are three and two, so my whole is.

My parts are one and four, so my whole is.

My parts are five and four, so my whole is.

My parts are two and five, so my whole is.

Good job it's seven.

And finally my parts are three and six, so my whole is, nine.

Great job if you shouted out all of those before I even flash them up on the screen.

We're going to have a look at some other ones now.

So we need to pause the screen now to fill in the wholes for each of these part whole models.

Okay, let's go through them then.

So if that my parts are one in seven, my whole is eight.

If my parts are two and eight, my whole is 10.

If my parts are one and three, my whole is four.

If my parts are two and four, my whole is six.

If my parts are two and six, my whole will be eight.

And finally if my parts are three and four, my whole will be seven.

I want you to have a look at this now.

So we know from this part whole model, this equation, we know that one add seven makes eight.

If I know that one add seven equals eight, can you think about what other number factor I know? I'm going to give you a few seconds to think about it.

Well, I know that if one add seven equals eight, then seven add one equals eight.

I can switch my two parts around one and seven and that will not change my whole, my whole will stay the same, even if I switched my parts around.

And that is because of Commutative Law.

My turn Commutative Law, your turn.

Fantastic.

We can see this for all of the other examples on our part whole module.

So if two add eight equals 10, then eight add two equals 10.

If one add three equals four, then three add one equals four.

If two add four sorry, equals six, then four add two equals six.

If I know that two add six equals eight, can you tell me what else I know? Well done.

Six add two will equal eight.

Let's look at this next one.

If three add four equals seven, then what else do I know? Fantastic.

Four add three equals seven.

And this is because of the Commutative Law, which enables us to switch our parts around and our whole will not change.

We're going to move on to the spinning game now, where you going to have a chance to make your own part whole models and decide what your whole is.

Watch this clip now to see how to use your spinner.

So here is my spinner and you can see that I've drawn it, it doesn't look very pretty.

It doesn't matter if it's perfect.

So this is my spinner and you can see I've got the numbers, one, two, three, four and five on it.

Once you've drawn or printed out your spinner, you're going to need to put a paper clip in the centre of your spinner like this, and then put your pencil in between it so that you've got something holding it down.

Once you've done that you can flick around your paper clip, which will act as the spinner and it will land on a number.

And those are the numbers you are going to use.

You can see from my images that my spinner has landed on the digit one and the digit three.

So pause the video now to get your spinner set up and then play the video when you're ready to play the spinner game.

So now that you know how to use your spinner, this is how we play the spinner game.

The first thing you're going to do is spin the spinner twice to get each part of your part whole model.

If you have someone with you, you could take it in turns.

You saw from the video that my parts were one and three.

So now I need to add my parts together to identify my whole.

So if my parts are one and three, my whole is four.

Pause the video now, to have a go at the spinner game yourself.

We're going to have a think about some number bonds within 20 now.

Okay, so have a look at the image on my board of the Idyllic village.

And I want you to think about these two questions.

How many ducks are there out of the pond? And how many ducks are there in the pond? So have a look for the ducks.

You might need to squint there all the way down here.

And can you see how many ducks there are out of the pond? And how many that are in the pond? Pause the video now, if you need a little bit longer to think.

I'm going to give you a few seconds.

Brilliant.

So you've probably counted that there are 11 ducks out of the pond and there are four ducks in the pond.

I want to know how many ducks there are all together? So to do that, I'm going to put my parts 11 and four into a part whole model.

So you can see my part whole model here.

One of my parts is the number of ducks that were out of the pond and that is 11.

So I've got one 10 and one one, 10, 11.

And one of my parts is the number of ducks that were inside the pond and that was worth four.

So I've got my full ones represent that.

To work out my whole, I need to add my two parts together so I can see that 11 add four is 10, 11, 12, 13, 14, 15.

So all together there are 15 ducks.

However, I can use my number bonds to help me work this out.

Let's have a look at my number bonds then.

If I know that one add four equals five.

So remember that there was one, one and four ones here.

Then I can use that so there we go.

One add four is equal to five.

Then I can use that to help me know, 11 add four is going to be equal to 15.

So, because I knew that one add four equals five, I could work out what 11 add four was.

There we go we've got off 15.

So 11 add four is equal to 15.

Let's look a little bit further into using our number bonds within 10 to work out our number bonds within 20.

Here's an example.

If I know this number bond, so three add two is equal to five, then I also know that 13 add two is going to be equal to 15.

Remember because of Commutative Law, I can switch around my two parts and my whole won't change.

So I could also say that two add 13 is equal to 15.

We also know if four, sorry, if five add four is equal to nine, then five add 14 will be equal to 19, or 14 add five will be equal to 19 because remember we can switch around our parts and our whole will not change.

That is because of the principle of Commutative Law.

Okay, onto your independent tasks guys.

So for independent task, you are going to derive facts within 20 from these equations that are given.

So I want you to be able to draw your tens and ones for each in a representation like I did for our ducts question in a part whole model.

And I want you to think of how many facts you can derive from these equations using the sentence term, if I know, then I know.

I'm going to do an example for you now, and then you can have a go at your own.

So I'm going to take the equation four add two equals six.

Okay, so I know that four add two is equal to six.

There are a number of different facts within 20 that I can take from this equation.

For example, if four add.

If I know that four add two is equal to six, I know that four add 12 is equal to 16.

So like that, like that.

I also know, that I can switch around my digits, I can switch around my parts even and my whole will not change.

So I also know that if four 12 add is equal to 16 then 12 add four is equal to 16.

But my facts don't stop there.

If four add two is equal to six, I can also say, or I also know that 14 add two is equal to 16.

I remember because of Commutative Law, I can switch my parts around.

So two add 14 is equal to 16.

Your challenge is to figure out how many different ways you can write your equations.

Pause the video now to complete your task, resume the video once you're finished.

Okay, so remember your challenge was to think of, how many different ways you could write your equations? So let's have a look at one example, we're going to go with three add six is equal to nine.

So if I know three add six is equal to nine, then I also know that 13 add six is equal to 19 or six add 13 is equal to 19.

I also know that three add 16 is equal to 19 or 16 add three is equal to 19.

That was just one example and from that one equation, we were able to come up with four more equations or derived facts for our number ones to 20.

That concludes our lesson for today team.

Well done on your really hard work today with using number bonds to 20 to help with addition.

I'll see you very soon on another session.

Bye, bye.

If you'd like to, please ask your parents or carer to share your work on Instagram, Facebook or Twitter, tagging @OakNational and hashtag LearnwithOak.

Now it's time to complete the quiz.

So when the video ends guys, don't forget to give it a go and recap everything you've learned in today's lesson.

Good luck.