# Lesson video

In progress...

Hi everyone, it's Miss Mitchell here, It's so great to see you.

Today 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'll 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.

Let's look at this problem.

Sally has three books, Megan has seven books.

How many more books does Megan have? What do we know, and what is unknown? How can we represent this using a bar model? We know that Sally has three books, so let's draw one, two, three squares on our bar.

We also know that Megan has seven books, so that's right Megan, one, two, three, four, five, six, seven.

What is unknown is how many more books, that Megan has.

But by looking at this bar, we can see that Megan has, one, two, three, four more books.

Up to this point they have the same amount, but then Megan has one, two, three, four more.

So by using this bar model, I can answer these questions.

I can see here that Sally has three books, one, two, three.

We can see here that Megan has seven books, one, two, three, four, five, six, seven.

We can see here that Megan has four more books.

Here they have the same amount, and then one, two, three, four more books.

This means that Sally has four fewer books, cause we can count backwards.

One, two, three, four fewer.

So what is the difference between Sally and Megan? The difference is four books, because my equation is seven take away three, is equal to four.

Megan has seven books, Sally has three books, seven take away three is equal to four.

That's how we can work out the difference.

Let's try a different one.

Jay has four footballs, Alex has eight footballs, how many more footballs does Alex have? What do we know and what is unknown? Pause the video now, to draw what your bar model would look like.

It is known to us that Jay has four footballs, so let's draw four squares.

One, two, three, four.

We know that Alex has eight footballs.

So let's draw eight squares, one, two, three, four, five, six, seven, eight.

What is unknown is how many more footballs he has.

But here we can see that Alex has, one, two, three, four more footballs than Jay.

So we can now use this bar model, to help us answer these questions.

We can see that Jay has four footballs.

One, two, three, four.

We can say that Alex has eight footballs.

We can see that Alex has four more footballs than Jay.

We can see that Jay has four fewer footballs than Alex, And you can see that here.

How will we work out the difference? What equation will I write? My equation will be eight take away four is equal to four.

That's how you work out the difference, the difference is four footballs.

Have a go at this one by yourself.

Mark has nine crayons, Lisa has five crayons.

How many fewer crayons does Lisa have? Pause the video, and draw what you think the bar model will look like.

What do we know and what is unknown? We know that Mark has nine crayons, and we know that Lisa has five crayons.

What is unknown is how many fewer crayons that Lisa has.

We can now use the bar model, to help us answer these questions.

Pause the video now to answer these questions yourself, we can see here that Mark has nine crayons, we know already that Lisa has five crayons.

And now this bar model will help us to see how many more crayons that Mark has, and we can see Mark has one, two, three, four more.

So that means that Lisa has four fewer crayons, as you can see here.

One, two, three lovely.

The difference between Mark and Lisa is four crayons, because I know that nine take away five is equal to four.

Let's do another one, but this time I'm going to make the numbers bigger.

Sally has 13 books, Megan has 16 books.

How many fewer books does Sally have? What if we don't have space on our paper to draw 16 squares? What could we do instead? We could just throw balls to save time, pause the video now, to draw what you think the bar will look like.

We know that Sally has 13 books, so we will draw a bar of 13.

We also know that Megan has 16 books, so we will draw a bar of 16.

When we are drawing our balls, I know that 16 is greater than 13.

Therefore 16 will be a longer bar, because it is a greater number.

What we don't know is how many fewer books Sally has.

This is the unknown, so I can label that too.

From this bar model, I can see that Sally has 13 books.

I know that Megan has 16 books.

Now have a think, how many more books does Megan have than Sally? Three, Megan has three more books than Sally.

How many fewer books does Sally have than Megan? Three, what is the difference? What's will my equation be? My equation will be 16 take away 13, which is equal to three.

So the difference is three.

Well done.

Let's do one final one before the independent task, Sally has 14 books, Megan has 16 books.

How many more books does make an have? Pause the video now to draw what you think the bar model will look like.

We know that Sally has 14 books, so we will draw a bottle of 14 and we'll label.

We also know that Megan has 16 books, so we draw a bar of 16.

We don't know how many more books Megan has, that is unknown to us.

So I can label that too, from this bar model, we can see that Sally has 14 books, Megan has 16 books.

Now have a think, how many more books does Megan have than Sally? Two, Megan has two more books than Sally.

How many fewer books does Sally have then Megan? Two, Sally has two fewer books than Megan.

What's is the difference and how will I solve this? 16 take away 14 is equal to two, so the difference is two.

You've done really, really well.

Have a go at answering these word problems, draw the bar models to help you answer the questions, pause the video now, and then press play when you are ready for the answers.

And here are the answers.

If you would 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 well done today.

Now go and complete the quiz, to see what you can remember, bye.