Lesson video

Hi, everyone, it's Miss Mitchell here.

Today in math we're going to be representing comparative word problems using bar models.

In today's lesson we'll be representing comparative problems using bar models.

We will be drawing comparative bar models, then I'd like you to complete the worksheet, and then a quiz.

For today's lesson you will need a pencil and some paper.

Pause this video now to get this, if you have not got it already.

Today we'll be looking at comparative word problems. But what does the word comparative mean? Can you say the word, Comparative? Comparative.

Can you say it one more time? Comparative.

And whisper the word, Comparative.

And really loudly, Comparative! Fantastic.

The word comparative, which really sounds like the word compare.

Put your hands up if you've heard of the word compare before.

The word compare means when you've put two or more things together and you want to see the similarities or differences about them.

Let's look at this word problem.

Ben has four crayons.

Levi has two more.

How many crayons does Levi have? What do we know? And what do we not know? How can we represent this using a bar model? We know that Ben has four crayons.

Let's write his name and draw: one, two, three, four.

Fantastic.

Now we know that Levi has two more crayons.

He has two more crayons than Ben.

So Levi has: one, two, three, four crayons.

But then he has two more: one, two.

We can now see that Levi has six crayons.

Because he has two more than Ben.

We can now answer these questions.

We can see that Ben has: one, two, three, four crayons.

We can see that Levi has: one, two, three, four, five, six crayons.

We can see that Levi has two more: one, two.

Because up to here they have the same amount.

And then Levi has the one, two more.

Ben has: one, two, fewer crayons than Levi.

One, two, fewer, because then they have the same amount.

So the difference between Ben and Levi is two crayons.

To work out the difference we can use subtraction.

And six take away four is equal to two.

Great! Let's try a different problem.

Levi has six crayons.

Ben has two fewer.

How many crayons does Ben have? What do we know? And what do we not know? We know that Levi has six crayons.

So let's write his name.

One, two, three, four, five, six.

Now we know that Ben has two fewer, but what is unknown is how many crayons that Ben has.

So if Ben has two fewer than six, my equation will be six take away two, because he has two less, two fewer.

What is six take away two? Four.

So Ben has: one, two, three, four crayons.

Because he has one, two fewer.

We can answer these questions.

Ben has: one, two, three, four, crayons.

Levi has: one, two, three, four, five, six crayons.

Levi has one, two more crayons than Ben.

So Levi has two more crayons than Ben.

That means that Ben has one, two fewer crayons than Levi, because then he has the same amount, as you can see here.

Can you remember what operation I used to work out the difference? That's right, subtraction.

What will my equation be to work out the difference? Six take away four, which is equal to two.

Well done! I'm going to read this problem out and then I'd like for you to have a go by yourself.

Draw the comparative bar models and think about what information you know, and what information you don't know.

James has five pens.

Sheri has three more.

How many pens does Sheri have? Pause the video now.

Well done.

We know that James has five pens.

One, two, three, four, five.

We know that Sheri has three more pens.

But what is unknown is how many pens that Sheri has.

What is three more than five? We know that Sheri has five: one, two, three, four, five.

But we know that Sheri has three more: one, two, three.

So we can now answer the question, how many pens does Sheri have now? One, two, three, four, five, six, seven, eight.

Sheri has eight pens.

We can now answer these questions.

James has: one, two, three, four, five pens.

Can you please tell me how many pens does Sheri have? That's right, eight pens.

One, two, three, four, five, six, seven, eight.

Can you please tell me how many more pens does Sheri have? Sheri has: one, two, three more pens.

Can you please tell me how many fewer pens does James have than Sheri? How many fewer pens does James have? That's right, James has three fewer.

One, two, three.

Can you please tell me what the difference is? And also can you tell me how you work that out? That's right, the difference is three pens and my equation would be eight take away five is equal to three.

Let's try another one.

Sheri has eight pens.

James has three fewer.

How many pens does James have? Pause the video now, think about what you know and what we don't know, and then draw the bar models please.

We know that Sheri has eight pens.

One, two, three, four, five, six, seven, eight.

We know that James has three fewer, but what is unknown is how many James has.

What is three fewer than eight? What is three less than eight? Eight take away three is equal to five.

So James has: one, two, three, four, five pens.

Because he has: one, two, three fewer.

Pause the video now to see if you could answer these questions.

By looking at this bar model I can see that James has five pens.

One, two, three, four, five.

We can look at this bar model and see that Sheri has eight pens.

One, two, three, four, five, six, seven, eight.

We can see that Sheri has three more pens.

One, two, three.

We can also see that James has three fewer pens.

One, two, three.

What is the difference and what operation do I need to use? And the difference is three pens.

'Cause eight take away five is equal to three.

Well done.

Let's see if you can have a go at the Independent Task.

There are four questions.

Draw comparative bar models to answer the question.

When you're ready, pause the video now.

Press Play when you're ready for the answers.

And here are the answers.

Well done, you've worked really, really hard today.

If you'd like to share your work with Oak National, then please ask your parent or carer to share your work on Twitter, tagging: @OakNational and #LearnwithOak You've done so much learning.

Now let's see what you can remember by completing the quiz on the next slide.