Lesson video

Hello, my name is Miss Robson.

In this lesson, we are going to be subtracting by counting back in ones.

We're going to start by looking at some subtraction math stories before practising counting back on a number line.

We're then going to apply those things to a really fun, independent task, all about sweets in jars.

And finally, it'll be time for you to complete a quiz.

For this lesson, you will need a pencil, some paper, a die and some objects for counting.

You might also need some colouring pencils if you have some around, or Crayons.

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

We're going to start by practising our number bonds.

On the screen are some different number bonds represented as bar models.

Some of the number bonds have been hidden by squares with question marks on them.

The first bar model is seven as the whole and zero as the other part.

There's no yellow part at all.

The next one is six and something.

Then, something and two.

Pause the video here to see if you can figure out what's missing underneath the question marks.

When you're finished, press play.

Here are the answers.

Let's go through them together.

Seven and zero make seven.

Remember to join in with the full sentences if you can.

Six and one make seven.

Five and two make seven.

Four and three make seven.

Three and four make seven.

Two and five make seven.

One and six make seven.

Seven and zero make seven.

Fantastic, well done.

We're going to start with some subtraction math stories.

I'm going to start by telling you a story about what I had for lunch today.

I had, I thought I was really thirsty.

And I was quite thirsty so I got six glasses of water.

That's a lot of water, isn't it? I prepared myself six glasses of water because I thought, maybe I would be able to drink that much.

I've got six beads to represent my glasses of water and I have six cubes, as well, in my whole.

So, I started with six.

But do you know what? My eyes were bigger than my belly because I couldn't drink all that water.

I drank four glasses.

So, take away four.

I drank four glasses but I couldn't drink any more than that.

Take away four, I've drunk four.

Six take away four is equal to two.

Six take away four is equal to two.

You can see that written as an equation.

Six subtract four is equal to two.

The whole, six, take away four, because I drank four glasses, is equal to two.

There were two glasses left with some water in them.

Let me tell you another math story.

This time, I made dinner for my family.

I made six salads.

That's a lot of salad, isn't it? Six salads.

They were all different kinds of salad but there were still six of them.

Six salads.

And do you know what? Nobody was as hungry as I had hoped they would be.

I made all six salads but we only ate one of them.

Six take away one.

Can you count for me? How many are left in the whole? There are five cubes left in the whole.

There are five salads left.

Now, I need to move those to my second part.

Because one is a part and five is a part.

One is the amount of salads that we ate.

Five is the amount of salads that we couldn't eat because it was too much and the whole is six.

All together, I made six salads.

Let's look at that as an equation.

Six, remember, I made six salads, take away one, because that was the only one that we managed to eat.

There were five salads left that we did not eat.

Six subtract one is equal to five.

Can you say that sentence with me? Six subtract one is equal to five.

What we're going to do now is we are going to look at how to play a subtraction game.

This game is a lot of fun.

I am going to show you an example and then it will be your turn to have a go.

For this game, you will need a part-whole model, which you could draw on your piece of paper.

Or, if you didn't have one, you could just put your things into groups and make sure that you remember where you're moving your groups to.

You will also need the cards that you can see on your screen.

Subtract zero, subtract one, subtract two and subtract three.

If you'd like to, you could write these on a piece of paper, too, and rip them up into pieces and use them.

Or, you could just point to the different ones on the screen that you'd like to use.

You will also need your die.

What I do is I start by rolling the die.

I landed on the number five.

I rolled a five.

I'm going to put five cubes in the whole.

There are five cubes in the whole.

I could also have five beads on my string.

Five.

Now, I'm going to choose how many I'd like to subtract from that.

Let me put a story to this to help me remember, to help me think it through.

I had five hair brushes, five hair brushes.

All of my cubes in my whole there can represent my hairbrushes.

I'm going to subtract two.

Looking at the choices on the screen, I have subtract one, oh, sorry, subtract zero, subtract one, subtract two and subtract three.

I'm going to choose to subtract two.

So, I need to move two of them to the other part.

There we go.

Two of my hairbrushes broke.

Five all together.

Two of them broke.

I've subtracted them.

Which means that my other part is three.

Trying to say that in a full equation is five subtract two is equal to three.

Can you say that with me? Five subtract two is equal to three.

Fantastic.

Looking at the part-whole model, five subtract two is equal to three.

My parts were two and three and the whole is five.

Have a go at rolling your die and then choosing how many to subtract and seeing, maybe, if you could put a math story to it, too.

You could have a go at recording the equations if you like or you can just try saying them like we did.

Five subtract two is equal to three.

Pause the video, now, to complete some equations.

When you've done a few, press play.

Now that you've practised doing some subtraction by partitioning, that was what we were just practising with our talk task.

We were subtracting by gathering all of our items and taking away a few from the main group.

We're now going to practise counting back on a number line.

In the whole I can see six.

I had six tomatoes growing in my garden.

Then, along came a cheeky cat.

The cat knocked four of the tomatoes off of the vine.

I had six all together on the vine and the cat took four off.

Six take away four.

Let's use our number track and our number line to check how many I have left.

I start at six, I start at the whole.

I'm going to bounce back four.

One, two, three, four.

There are two tomatoes left.

You can see the two left here.

I need to pop them in my other part.

Four is a part, two is a part, the whole is six.

Let's try that on the number line, as well, to make sure it works.

Starting at six and jumping back four.

One, two, three, four.

Six take away four is equal to two.

Six, the whole, take away four, four tomatoes were stolen by the cat, is equal to two, I have two left on the vine.

Let's tell one more math story using the number line.

I have my six back in my whole.

This time, these cubes are going to represent six lamps that I have in my house.

One day, one of the bulbs in the lamp went out.

It blew, which means that it didn't work anymore.

I had six lamps.

One of them broke, the bulb blew.

I had six lamps and one of the bulbs blew.

I'm going to jump back one.

Ready? One.

There were five left.

Let's check on the number line, starting at six and jumping back one.

One, there were five left.

You can see five are left in the whole here.

I need to move the five to the part.

Because the whole was six.

I took away my one lamp that broke and now I have five left.

Six is how many lamps I had to start with.

Six is how many lamps I had first.

One is how many lamps broke.

And five is how many lamps I have left, now.

Now, it's time for you to complete the independent task.

I'm really excited about today's independent task because it is such fun to play.

You can see a board game in front of you.

There are lots and lots of squares with lots of equations in them.

Let me read the instructions.

Choose a square, and using the number line to jump back, complete the subtraction.

Find the answer at the top, and use that colour to colour in the square with that equation.

Let's do the first few together.

Let's start at the very beginning.

It's a very good place to start.

We're going to start with this one here.

This one here is seven take away three.

So, I come down to the number line to seven and I'm taking away three, I'm jumping back three.

I need to jump this way.

Are you ready to help me? One, two, three.

Seven take away three is equal to four.

Can you say that full sentence? Great.

That means I go up to the top.

Seven take away three is equal to four.

I need to choose the right answer.

It will be green.

Let's colour that square in green.

Look at my little zigzags through.

Next, I'm going to do seven take away two.

I'm going to come back down to the number line.

Seven and I'm going to take away two.

Jumping back two.

Count with me.

One, two.

Seven take away two is equal to five.

At the very top, I find the number five.

The number five is white so I might use a bit of a grey colour.

There we go.

I've coloured in that square white.

Let's do one more together and then it's your turn.

This time there is seven take away one.

That one's pretty easy.

I can do that in my head because that is just one less than seven.

But let's check on the number line to make sure.

I think one less than seven is six.

Ready? Here's seven.

One less is six.

Fantastic.

What colour should I colour that square in, then? Have a look at the top and see if you can tell me.

I need to colour that square in.

That's the answer.

Seven take away one is equal to six, which means I need to colour in the square in orange.

It's time, now, for you to go and finish the rest yourself.

If you don't have any colouring pencils, you could just write the colour in the box.

Afterwards, you could have a look and see if you can spot any patterns.

It's time, now, for you to complete the independent task.

Pause the video here to complete the task and when you're finished, press play.

I hope that you've enjoyed that as much as I enjoy doing that activity.

Here, I can see the completed square.

Remember, mine are computer squiggles, so they're not probably as nice as your colouring in.

But I can see all of the different squiggles.

Actually, I noticed something about them.

What can you spot about those colours? Pause the video to have a really good look if you're a bit stuck.

I can see that they're in a pattern.

I can see a diagonal pattern.

I can see greens going all the way down here.

I can see another pattern in, actually in the numbers.

There are sixes in this row.

Sixes take away something.

Sevens take away something.

Fives take away something.

And also, patterns going this way.

This is all take away zero.

This is all take away one.

And this is all take away two and all take away three.

There are lots of different patterns going on in that.

I hope that you enjoyed that activity.

What a fun way to practise counting back on a number line.

If you'd like to, please share your work with us.

If you want, ask your parent or carer to share your work on Instagram, Facebook or Twitter by tagging @OakNational and using #LearnwithOak.

We'd love to see what you've been getting up to.

Thanks for joining me, today.

See ya next time.