Lesson video

Hello year 2, and welcome to today's session.

We're going to be carrying on our unit, which is exploring calculation strategies.

And today's session we're going to be solving comparison word problems. For this lesson, you will need a pencil and some paper.

Please pause the video now to go and get these things, if you haven't got them all ready.

Okay, I thought I'd start today's session with a little riddle.

What has four legs, but can't walk? Have a think, has four legs that can't walk.

Well done to those of you who guessed it correctly.

It is in fact a table, right? Then let's get started.

So, our agenda for today's session.

We are going to be learning how to solve comparison word problems. We're going to start with a quiz to test your knowledge.

Then we're going to look at today's star words.

We're going to look at some word problems. Then you are going to have to get your talk task.

Then together, answer the word problems. Then there'll be an independent task and we'll review the answers together.

And there'll be a final quiz for you to see what you have remembered.

Please pause the video now to do your starter quiz.

Okay, welcome back year 2, let's do today's style words.

We're going to do them, my turn, your turn.

So fewer, more, unknown, difference, known, less, add, subtract.

Well done year 2, let's have a look then at today's new learning.

So, we've got a question.

It says, question one: Sam and Jo are measuring some wood to build a bench.

Sam has a plank of wood which measured 96 centimetres.

Jo has a plank of wood measuring 21 centimetres.

How much longer is Sam's plank of wood than Jo's? The first things I want to ask to consider are, what do we know? What don't we know? We're not going to solve this question just yet.

We're going to think about how we solve it best.

So, what do we know? Well, we know that sam's plank of wood measures 96 centimetres.

And we know that Jo has a plank of wood that measures 21 centimetres, the unknown.

So what we don't know is how much longer Sam's plank of wood is than Jo's plank of wood.

So in order to solve this, we need to think about what our equation would be.

That would help us to resolve the answer to our question.

So we would have 96 centimetres and we want to take away 21 centimetres to give us an answer, our unknown.

We could think about it like this, we'd have 21 centimetres, but we don't know what that value is.

I guess, as all the way up to 96 centimetres.

So could show it as 21 centimetres, less something is equal to 96 centimetres.

We're not going to solve the equation just yet.

We're going to have a look at question two and then we'll do our talk task and also about equations.

So question two says: An apple weighs 58 grammes and banana weighs 19 grammes more.

How much does the banana way? So what do we know? Well, we know that an apple weighs 58 grammes.

What we don't know, and we also know, sorry.

That a banana weighs 19 grammes more.

What we don't know though is how much a banana actually weighs.

We know that it weighs 19 grammes more than the apple.

We don't know what that value is.

So if I had to write it out as an equation, I would write, "58 g + 19 g =?g" the weight of our banana, but we don't know what that value is at the moment.

Let's have a go at today's talk task first.

So you're talk to us today.

You have got some questions and I'd like you to have a go at matching these questions to the correct bar models.

Remember, read through the questions, really carefully looking for that key information before you match that with the bar models.

Use the say it out loud to help you.

This bar model matches this word problem.

Pause the video now to have a go at today's talk task, we will go through the answers afterwards.

Okay, welcome back year 2, well done for working really hard so far, let's have a look there at how our questions match with our bar models.

So I'm going to read the first question here and then we'll match it with a bar model.

An orange weighs 62 grammes and a peach weighs 34 grammes.

How much more does the orange weigh than the peach? That question matches with this bar model down here, we can see an orange with 62 grammes and our peach weighs 34 grammes.

We don't know how much more the orange weighs at the moment than the peach, so our missing number is here to find out.

Next question then: Max has 60 millilitres of medicine.

Ben has 30 millilitres of medicine.

How much less medicine does Ben have than Max? That question links with this bar model here.

Max has the 60 millilitres then has the 30 millilitres.

We want to find out how much less medicine Ben has than Max.

So we'd need to find out this missing value here.

Next question then: Lisa and James are building a swing.

Lisa has 62 centimetres of rope.

James has 34 centimetres more rope than Lisa.

How much rope does James have? Matches with this bar model here.

We know that Lisa has 62 centimetres of rope.

We know that James has 34 centimetres of rope.

We don't know how much more, how much rope, sorry, James has altogether.

So we don't know this missing value here.

My last question says: A can of fizzy drink cost 60p and sweets cost 30p less than the fizzy drink.

How much do the sweets cost? Matches that this bar model here, because we know our fizzy drink or 60p our sweets cost 30p less.

We don't know that missing value here.

Well done for working really hard today with today's talk task.

Let some of that develop learning before you have go at your independent tasks.

So back to those questions we looked at earlier.

Now we're going to have a go at solving them.

So let's have a look at them on a bar model.

I'm going to reread the question I'm going to re-look at the equations.

So Sam and Jo are measuring some woods to build a bench.

Sam has a plank of wood which measures 96 centimetres.

Jo has a plank of wood measuring 21 centimetres.

How much longer is Sam's plank of wood than jo's? We've already written it out as an equation.

I'm going to show you as a bar model, right? Here, you can see Sam in red.

We know his plank of wood is 96 centimetres long.

You can see Jo and blue.

We know his plank of wood is 21 centimetres long.

That unknown value is the value with the question mark here.

We want to know how much longer Sam's plank of wood is.

We've got our equation, "96 cm - 21 cm = ?" We need to have a quick think, what strategy could you use to help you solve that question? I want you to have five seconds thinking time about an appropriate strategy we could use to solve that equation.

Okay, all I know that from my strategies for subtraction, I could do some partitioning here.

I could partition 21 centimetres into 20 and one.

I could then put 96 on my head and count back 20.

Let's do that together, 96 in your heads.

We're going to count a fast times, twice 86, 76.

I'm going to pause there for a moment because I partitioned them, I then have to take away one.

So 76, they play one get back one is 75 centimetres.

So my missing number should be 75 centimetres.

I could say 21 centimetres add 75 centimetres equals 96 as well.

Let's have a look at example on question two.

So question two says: An apple weighs 58 grammes and a banana weighs 19 grammes more.

How much does the banana way? So let's have a look at our bar model.

We looked at the equation earlier.

A banana, we can see our banana here in red.

We don't know how much it weighs, but we do know that an apple here in blue weighs 58 grammes.

And we know that a banana weighs 19 grammes more.

So to work that out, we need to do 58 grammes of 19 grammes.

Wait, have a little think, what strategy could you use to solve that equation? A five seconds thinking time, and then we'll go through it together.

Alright, then let's have a look.

Well done to those of you who noticed that 19 is close to 20.

So what I would do is using random adjusts to make 19,20.

I would then ask two to 58.

So we're going to put 58 in our heads, 68, 78.

Oh, we then have to adjust because we've added on we now need to take that away.

That's going to give us 77 grammes check.

Absolutely 77 grammes.

Okay, then you're now ready to have a go at today's independent tasks.

But that's a days independent task you have got three slides.

You've got three questions on each.

I want you to read through these questions really carefully.

Looking at that key information.

Then I want you to have a go at solving them.

Remember to use those different addition and subtraction strategies that we've been talking about.

And remember, you can use a bar model to help you.

So, here is slide one and here's slide two.

Pause the video now to complete your task.

Welcome back year 2, we're going to go through the answers together now.

So, question one question one: Ellie and Becky baked a cake.

Ellie used 67 grammes of flour.

Becky used 34 grammes of flour.

How much less did Becky use than Ellie? So we have 67 grammes, subtract 34 grammes, gives us 33 grammes.

Question two: Anna had 27 pounds.

Jake has 14 pounds.

How much more money does Anna have than Jake? So, Anna has the 27 pounds, we need to take off 14 pounds to find out how much more money Anna has.

She has 13 pounds, more money than Jake.

Questions three: Lisa and James are building toy trains.

Lisa's train is 80 centimetres long.

James' train is 33 centimetre shorter.

How long is James' train? So we have Lisa's trains 80 centimetres long, James' train is 33 centimetre shorter, which is subtract 33 from 80, which gives us 47 centimetres.

Question four: A packet of biscuits costs 45p and a bottle of water costs 39p more.

How much does the water cost? So we know biscuits cost 45p, water cost 39p.

So we need to add them together to give us 84p.

Hey, sorry, it costs 39p more, so we know that it costs 84p.

Jay's paddling pool has 90 litres of water.

Sally's paddling pool has 78 litres of water.

How many more litres of water is in Jay's pool than in Sally's? So, we know Jay's pool has 90 litres.

We know Sally's pool has 78 litres.

We want to know how many more litres are in Jay's pool.

So we need to subtract it from Sally's which is 78 from Jay's which is 90 to get us 12 litres.

And our last question question six says: Alex walks 58 metres to her bus stop, but she walks 17 fewer metres to school.

How far did she walk to school? So we know that she walked 58 metres to her bus stop, and she walked 17 fewer to school.

So we need to take it away from the initial 58 metres, which gives us 41 metres.

Well done to all of you for working so hard today.

I've been really, really impressed.

What I would like you to do now is pause your video to go to the final quiz to answer a few questions based on what we've been learning today.

Thank you very much for joining me and see you again soon, bye.