Lesson video

Hello, I'm Ms. Brinkworth I'm going to go through this math lesson with you today.

Should we get started? So today's learning objective, is that we're just going to be looking at consolidating all of that multiplication and diviling division knowledge that you've built up, recently.

So we're going to.

hopefully a lot of this lesson will be revision we'll be recapping.

So it would be a chance for you to really consolidate that means make really secure, really strong, all of that multiplication and division knowledge that you have taken on recently.

So if we look at our agenda, we're firstly going to look at doubles and 10 times greater.

Those are little tricks that we have in a way that allow us to apply our known facts to different contexts.

We're then going to have a look at factors and products and just make sure that we are really clear on what that key vocabulary is all about.

We're going to have a look at bar models so the most appropriate bar models to answer word problems and Elizabeth correspondence as well.

And then finally you will have time for some independent work and an exit quiz's job just to really say how well all of this unit on multiplication and division has gone in.

Okay.

So all you're going to need is a pencil and paper and a big smile.

So pause the video and get what you need.

Welcome back.

Let's get started.

So, at least a warm-up, have a look at these multiplication and division facts.

One of them is the odd one out.

Can you work out which one it is? And can you explain what makes it the odd one out? Well, well done if you spotted, that this one here is a bit different from the others.

It doesn't sit within the same fact family.

All of the others use nine times five is 45 in some way or another.

This one is using a tut slightly different facts family.

So this slide just reminds us, that we can use one simple fact like nine times five is 45 in lots and lots of different questions both multiplication and division.

We can make it 10 times bigger et cetera.

So hopefully in what today's lesson's going to do is really consolidate some of this learning, put it together so that you start feeling really confident, applying that knowledge in a range of different types of questions.

So we're going to get started by looking at doubling.

How we can double our threes and our fours to help us with our six and our eights.

So, three times three is nine and three times six is 18.

So I've used nine and I've doubled it to get me 18.

I know I can do that because three times two is six and so three times nine is a similar question.

So three times three gives me nine is a very similar question to three times six is 18.

I can just double my answer.

Use that then and tell me what my answer is going to be here.

If two times.

if three times two is six, what's three times four? Well, we just need to double six don't we? And hopefully we'll know that double six is 12.

So let's have a little bit more of a look at that doubling that we can do.

So we looked at four times three is 12 four times six is 24.

I've doubled three in the question and so my answer has doubled as well.

So, if we are stuck on our sixes, we can always use our threes to help us.

Similarly, if we're stuck with our eights, it's our fours that come in to help us.

So this slide, shows why threes and sixes, have that relationship.

Six is double three.

And so, if I want to find four times six, I can double three.

four times three.

So four times three is 12 and four times six is 24.

For an eight half that's same relationship where eight is double four, four is half of eight.

So.

if you see that number line at the bottom you can see that for every jump of eight it goes twice in our fours.

So we can double our fours to find our eights.

One four is four and one eight is eight, four fours are 16.

To double 16 I could think of it as double 15.

At two, double 15 is 30 add two more is 32.

So double four is six.

sorry four times four is 16, four times eight is 32.

Use that then to have a go at answering these questions.

You've been given the facts on the left and they will help you with all of the questions on the right.

All you need to do is double.

How did you get on? Were some easier than others? Some numbers are easier to double than others.

And if you need to write them out maybe do a tiny little bit of column addition.

That's fine.

But as you move through and become more confident, I'm hoping that you'll be able to do these in your head as well.

So double 15 I've talked about that fact already double 15 is 30.

That might just be a really important fact to learn.

So if you don't know that maybe write it out a few times.

Double 15 is 30 it will come in handy for lots of questions I promise.

Double 24 that's a nice one to double cause we know that there's no regrouping needed to double forwards eight and double 20 is 40, 48.

Double 16 we've talked about that one already.

If you know that double 15 is 30 and you just add the extra twos on the 32, and then again double 24 is 48.

So you can see that the same facts come up a lot of the time.

Okay.

Our 10 times table then we've talked about doubling as a way of using our known number facts our known multiplications to help us answer questions in different contexts.

Our 10 times table can do exactly the same thing.

See here's a recap on what our 10 times table looks like.

I'm sure a lot of you are very confident with it.

And here's just a recap as well about why this happens.

Sometimes we're tempted to think of doubling.

of timesing by 10 as adding a zero on the end.

Let's try and move away from that and think of it instead about each digit moving one decimal place to the left being made 10 times bigger shifting along.

So when we multiply one by 10 our one moves from the ones column into the tens column and you can see that there with that place value column.

So, our six go to 60, six moves from the ones into the tens.

This is how we multiply by 10 and it can really help us with our multiplication questions if we know how to multiply by 10.

So really quickly have a go at answering these questions shouldn't take long at all.

Great.

Just a real recap on your 10 times tables.

I'm hoping you all got those right.

Now, we can use that to help us with these.

So have a go at answering the questions in column A and then using them to answer the questions in column B, where the answer is you're going to use your times table knowledge and multiplying by 10 to find that answer.

Pause the video here and have a go.

Well done.

I'm hoping that you were able to use your knowledge of your known times tables.

So two three four five and that knowledge of how we can make the answer 10 times bigger, moving them on place on the place one decimal place in the place value columns, and answer these questions.

So let's go through them together.

Two times by seven I know that that one is 14.

That can then help me with this part here, 20 times by seven.

20 is two made 10 times bigger.

So my answer is going to be 10 times bigger than 14, which is 140.

Four times three that's the fact that is really important to just know straight away.

Four times three is 12.

Well then if you just know that.

If you can't it might be worth practising writing it out and getting people to test you.

But when we make that 10 times bigger, for four times 30, we get 120.

Four times five.

Our five times tables is it's 40.

And when we change that to 80 times five where eight is 10 times bigger, the answer gets 10 times bigger for 400.

Nine times three or three times nine whichever way around you want to answer that question is 27.

Made 10 times bigger, 270.

And finally four times four one that I have to remind myself about quite a lot is 16 and made 10 times bigger is 160.

If you got all of those right really really well done, if you didn't, just have a little bit of a practise cause there are two things going on to answer these questions.

You've got the initial times table knowledge the ones in column A.

And then you've got that ability to make the answer 10 times bigger.

So if you do just need to have a little bit more of a practise you could make up some other questions for yourself.

Any of the times tables that you're confident with and just think about making one of the factors 10 times bigger.

So for example if you're already confident with your twos and you know two times four and you know two times six and you know two times eight, then you have a go at 20 times two and 20 times four for example.

Okay.

Here we are then where we have.

where we are cooking up bar models.

So we have word problems that require multiplication in their answer.

And then this is idea about which bar-model is most appropriate to answer the question.

So for this one, Robin Hood shot his arrow three times as far as the Sheriff.

The Sheriff shot his arrow 20 metres.

How far did Robin Hood's arrow go? Well the most appropriate bar model to use here, is actually the one on the right.

It's not showing a part-whole relationship.

It's showing that what we need to do to 20 is make it three times bigger.

And then we'll find our answer.

Have a go at matching these word problems with the bar model.

You're not actually answering the problem you're just finding the most appropriate bar model.

Well done.

Let's see how you got on.

So here's how they match up.

And it's not just about the numbers being on the bar models.

And that would've been a way of matching them up but it's also about whether the bar model matches the question in terms of part-whole or greater than.

Okay.

Factors and products finally before you get onto your independent task.

If you look at two times three equals six at the top there.

I've put two and three in pink because they're your factors.

And six is your product it's in green.

So remember the product is the thing that is made.

So when we take two and three what we make when we multiply them together is six.

So have a go at matching these factor pairs, with the appropriate product.

What happens when we multiply those numbers together? Well done.

So like I say we talk about the factors in pairs, and when we multiply them together, we get products.

So the product of three and five is 15.

Three times five is 15.

The product of eighth and four is 32.

Seven and three.

Oh mixed that one up eight and 10 is 80.

12 and two is 24 and seven and three is 21.

Oh mixed that one up.

Seven and three is 21.

Okay.

So time for your independent task.

Pause the video, have a go, I'm hoping a lot of it will be revision for you.

Come back together and we'll talk about the answers.

How did you get on? Let's have a look at which questions you got right and whether there were any that need you to do a little bit more independent work on them.

So use what you know about doubling and making 10 times bigger to answer these questions.

So you've got those skills now where you know about you can double your threes to answer your sixes, and you can make 10 times bigger.

But now you need to think about what questions require that of you.

So 30 times six, that looks like a 10 times bigger question because we have a multiple of 10 there.

So I can use three times six which is 18 to help me answer 30 times six which will be 18 made 10 times bigger.

Four times eight? Maybe you just know that in your fours or your eight times tables and that's great.

But if you don't, you could do four times four is 16 made two times bigger is 32.

Again three times 90? we've got a 10 times bigger question there because we've got a multiple of 10 in 90.

So two times nine is 18.

So we've got 180 again there for two times 90.

Three times 12? Well, you might want to think of that as a doubling question.

You could do three times six for example.

Up to you whichever way you want to see that question but the answer is 36.

60 times five? We have a multiples of 10 question.

So 6 times 5 is 30.

60 times five is 300.

Six times three again you might want to see that as a doubling question.

Three times three is nine make it two times bigger is 18.

And then we've got another make 10 times bigger.

Five times five is 25.

So five times 50 is 250.

Well then we're nearly there you've worked fantastically well.

Well done if you were able to spot the mistake here.

It's this question.

90 times three is not 207.

Someone's made a little bit of a mistake with the order of their numbers.

Now, when you make 10 times bigger, remember that did the numbers staying next to each other.

So nine times three is 27, the two and the seven still staying next to each other, the right answer would've been 270.

We just moved them one one place one column in the place value columns.

And so 27 becomes 270.

Well done.

Your bar models might look completely different to mine, as long as they would help you answer the question that's fine.

So here's 24 tomatoes split onto three plates.

How many does each plate get? And this one is what you might have for the second question.

During a race Maid Marion won in eight seconds but it took Robin Hood three times as long.

So it's not a part-whole model for that one.

Okay.

Really really well done.

If you'd like to share your work with us today please do ask a parent or carer first to share your work on Instagram, Facebook or Twitter tagging @OakNational and #LearnwithOak.

There's a final knowledge quiz as well just as a little bit of a recap on that multiplication and division work.

So please do that before you go.

Otherwise, please enjoy the rest of your day and lots of really really hard work done today guys.

Well done.

Buh-bye.