Lesson video

Hi, everyone.

Really good to see you.

I'm all set for about 20 minutes of maths learning.

Are you? If you are in a noisy place or you have anything around you that could cause a distraction, then please press pause in a moment, take yourself off somewhere that's well away from that noise and distractions, so that you can focus on your learning, with me as I say for about 20 minutes.

Press pause now and come back as soon as you're ready.

In this lesson, we are multiplying and dividing by 100 with decimals.

In this lesson, we are multiplying and dividing by 100 with decimals.

We'll start off with a quick activity, where I'll get you to get you to do some ordering of decimals.

Then we will look fast of all at multiplying by 100, then dividing by 100 and we'll finish up with an independent task where you can apply those newly developed skills too.

You're going to need, something to write with, a pen or pencil, a piece of paper or a book and maybe a ruler handy as well.

Press pause, collect the items, come back and we'll start.

Here is our first activity.

So if you've got to ruler, it will be handy.

Now, I'd like you to estimate the position of those six decimals along the number line, spaced between zero and one.

Estimate, whereabouts on the number line would each of those decimals fall.

Press pause, give it a go, get ready afterwards to come back and share.

Ready, hold up any thing that you've written down, any number lines that you've drawn, let me have a look at the position of those decimals.

Good, really good, well done.

Let's take a look.

So, it helped me, to imagine this number line divided into 10 equal parts, because, three of those decimals are decimal tenths, seven tenths, six tenths, four tenths.

If I visualise a number line, divided into 10 equal parts, I can more accurately estimate the location of those decimal tenths and actually the decimal hundredths as well.

Because of course six tenths is 60 hundreds.

Seven tenths is 70 hundreds.

If I can estimate where they are, then I can find an estimate where 66 hundreds would be.

So I started with 0.

55.

I know that that's 55 hundreds, halfway is 50 hundredths, 55 hundreds, it's fairly close to halfway.

From there i plotted 0.

4.

So I know that that is closer to zero than to halfway.

So I need to mark it off, halfway.

0.

6 is closer to 0.

55 than 0.

4 is to 0.

55, it's five hundreds away.

And 0.

66 is six hundreds away.

So the spaces between, I've chosen based on how far apart the numbers are, 0.

7 is just four hundreds away.

And then, 0.

95 is quite it's further away than any of the numbers I've used so far as I've compared.

There's a big gap between 0.

7, 70 hundreds and 95 hundreds.

And it's very close to one, very close to 100 hundreds.

I've now laid the number line that I was visualising above the one I've worked with and I didn't use it.

I just visualised.

And you can see that some of the numbers are fairly on mark.

For example, four hundreds Fort sorry, 40 hundreds four tenths.

Some of them are not exactly in the right place, but this was an estimate, five tenths, 50 hundreds would be here.

So perhaps my 0.

55 needs to move a little bit more to the right, but I'm fairly pleased with that.

And it was the visualising that helped.

Are you pleased with how you did? Did you visualise a number line or would you maybe use that technique another time? How did you do it? What were you thinking about to help you place those decimals, really important to reflect on the process that you took there.

Okay, multiplied by 100.

Say what you see.

Three tens, thirty.

Good.

So when we multiplied by 100, each part of the number, is made 100 times bigger.

One 10, 100 times bigger is one thousand.

So three tens, 100 times bigger is good.

3000, say the equation or a bit louder.

Good.

Say what you see? Three ones, three, three multiplied by 100, one multiplied by 100, made 100 times bigger is 100, three, 100 times bigger.

Three multiplied by 10 is three hundred.

Good.

Let's say the equation together.

One, two, three, three multiplied by 100 is equal to three hundred.

Say what you see? Three tenths, 0.

3 multiplied by 100.

Each part made 100 times bigger.

What would it become? Good.

Three tenths, three tenths made hundred times bigger.

Three tens.

You say the equation.

Good.

Last one.

What do you see? 0.

03 multiplied by 100.

Each part made 100 times bigger.

Three.

Should we say the equation together? One, two, three, 0.

03 multiplied by 100 is equal to three.

Time for you to practise the skill, of multiplying by 100.

Can you choose any of those numbers? Use some drawings of place value counters to show that number and how it changes.

Write the equation for me, press pause.

Have a go, at multiplying some of these numbers by 100.

Come back when you've got something to share.

Ready to share.

Can you hold up your work for me? Let me look at the drawings you've used.

Can I see the before and the after? Can I see how those numbers have changed by multiplying by 100? Yes, I can.

Well done.

Here's one that you may have chosen.

What do you see? Five ones, made 100 times bigger will be, five hundreds.

Five multiplied by 100 is equal to five hundred.

Did you choose this one? What do you say? Seven tenths.

No.

Seven hundreds.

Good spot made 100 times bigger.

Seven ones.

Read the equation.

There it is.

Go.

Good.

Divide by 100.

What do you say? 5O00, five thousands.

When we divide by 100, each part of the number is made 100 times smaller, five thousand divided by one hundred, 1000 made 100 two times smaller is one 10.

One 10 is 100 times smaller than 1000.

What will 5,000 made? 100 times smaller be.

Yes, five tens.

Say the equation.

Good.

50, five tens.

Next.

What do you see, five hundreds? We're making it 100 times smaller.

One, one is 100 times smaller than one hundred.

So, what will be 100 times smaller than five hundreds? Good.

It will be five, five ones.

Let's read the equation together.

Five hundred divided by 100 is equal to five.

What do you see? Five tens.

fifty divided by one hundred made 100 times smaller.

Hmm, What would it become? Good, five tenths.

Five tens made 100 times smaller is equal to five tenths.

How do we say that as a decimal, 0.

5.

Read the equation for me.

Good.

Last one.

What do you see? Five ones.

Five made 100 times smaller.

What will be 100 times smaller than five ones.

Good, yes.

Five hundredths.

Say it for me as it as a decimal and let's read the equation together.

Five divided by 100 is equal to 0.

05.

Let's look at those connections between the division and the multiplication.

Can you read the division? My turn, 50 multiplied by 100 is equal to five thousand.

My turn 500 divided by 100 is equal to five.

Your turn.

Your turn, my turn, 0.

5 multiplied by 100 is equal to fifty together in a whisper five divided by one hundred is equal to 0.

05.

Still another whisper, 0.

05 multiply by one hundred is equal to five.

Good work.

Look at the connections.

Look at how, the numbers are made 500 times smaller.

When we divide by 100 and 100 times bigger.

When we multiply by 100, look at the connections, working down the division and down the multiplication as well, as the digits move from place to place.

It's time for your activity.

Here is a chart, full of numbers, full of patterns and connections.

I really like it.

I'm going to read an instruction to you.

Can you follow it? I start with the number 0.

4.

I multiplied by one hundred and then add twenty.

I divide by 10 and minus five.

I divide by 100.

What number have I ended up on? Tell me.

Good, 0.

01, For your activity, i would like you, using my example, to create your own set of five instructions.

Following some rules, you can use addition, subtraction, and multiplication by one hundred and division by one hundred, you could use the multiplication and division by 10 as well through your instructions.

You are allowed to move up, down, left and right, but not on a diagonal, Press pause, go and complete your task and come back when you've got five instructions written, how did you get on, five sets of instructions? Good.

Have you tested them out? Who won? Have you tried them with yourself.

Good, that's that's a good starting point.

Test them out yourself.

Do they work, then perhaps you could test them out with a teddy bear.

Favourite toy, a brother or sister, parent, or carer, maybe a friend, cousin.

The list is endless.

If you are able to try it out, when you share your work or your parents or carer shares your work on Twitter, let us know how that person got on.

If you'd like to share your work with Oak national, please ask a parent or carer to share your work on Twitter, tagging @OakNational and #LearnwithOak.

Well done everyone.

That was another fantastic lesson.

You've worked really hard.

You've engaged from the beginning through to the end.

I've really enjoyed those moments where you've held things up to the camera or you've joined in with chanting sentences numbers back and forth.

Thank you so much for your participation.

If you have any more learning lined up today, enjoy it and give it your all, just as you have in this maths lesson, I look forward to seeing you again soon.

Bye.