Lesson video

Hello there.

My name is Mr. Goldie, and welcome to today's math lesson.

I'm sure you're going to have lots of fun.

And here is our lesson outcome.

I can write a three digit multiple of 10 as a multiplication equation.

And here are our keywords.

I'm going to say each word, can you repeat them back to me? So the first key word is equation.

Can you say that? Equation.

Excellent.

And the second key word is multiple.

Can you say that? Multiple.

Brilliant.

And let's look at what those words mean.

An equation is used to show that one number or calculation is equal to another.

A multiple is the result of multiplying a number by another whole number.

So 10, 20, and 30 are all multiples of 10.

Two, four, six, and eight are all multiples of two.

And here's our lesson outline.

So the first part of the lesson, we are going to be looking at three digit numbers as an amount of tens.

And in the second part of the lesson, we're going to be using multiplication to show a number of tens.

Let's get started.

In this lesson today, you will meet Sophia and Andeep.

Sophia and Andeep think about how to show tens.

"You can use base 10 blocks," says Andeep.

This represents 10, this represents 100 or 10 lots of 10.

"You can use hundreds frames," says Sophia.

This represents 10.

This represents 100 or 10 lots of 10.

Andeep represents a number using base 10 blocks.

How many tens are represented? So 100 is equal to 10 tens.

So that 100 there is equal to 10 tens.

And that 100 there is also 10 tens, and there are two extra tens.

10 + 10 + 2 = 22.

There are 22 tens altogether.

"22 tens = 220," says Andeep.

Sophia represents a number using hundreds frames.

"How many tens are represented?" says Sophia.

So a hundred is equal to 10 tens, remember.

That first hundreds frame is equal to 10 tens, this hundreds frame is also equal to 10 tens, and then there are four extra tens.

10 + 10 + 4 = 24.

There are 24 tens altogether.

24 tens = 240.

Andeep represents a number using base 10 blocks.

"How many tens are represented?" says Andeep.

So remember, 100 is equal to 10 tens.

So the first 100 is worth 10 tens, the next 100 is also equal to 10 tens.

And this 100 here is also equal to 10 tens.

And there are five extra tens.

So 10 tens + 10 tens + 10 tens = 30 tens.

And then we've got five extra tens.

30 + 5 = 35.

There are 35 tens altogether.

35 tens = 350.

So Andeep used an equation there to say that 35 tens = 350.

Sophia represents a number using hundreds frames.

"How many tens are represented?" says Sophia.

There's quite a lot of tens this time, aren't there? How many tens are represented? So there are four lots of full hundreds frames, so that's 10 tens + 10 tens + 10 tens + 10 tens, which equals 40 tens.

And then there's an extra five tens.

40 + 5 equals 45.

There are 45 tens altogether.

45 tens = 450.

So the hundreds frames represent 45 tens and they also represent 450.

Here's one to try on your own.

So Andeep represents a number using base 10 blocks.

"I've represented 37 tens," says Andeep.

And there's Andeep's representation.

Is Andeep correct? Pause the video and have a think.

And welcome back.

Let's see how you got on.

So is Andeep correct? Has he represented 37 tens? No, Andeep is not correct.

His representation shows 30 tens and 7 ones.

So he's got 30 tens.

So 100 + 100 + 100 is equivalent to is equal to 30 tens.

But he's got 7 ones, not an extra seven tens.

Andeep represents 280 using a bar model.

200 = 20 tens.

10 tens + 10 tens that's 20 tens.

So the 200 part of 280 = 20 tens.

80 = 8 tens.

There's our 8 tens.

280 is made out of 20 tens and 8 tens.

Sophia represents 310 using a bar model.

300 = 30 tens.

So 100 is equal to 10 tens, so 300 is equal to 30 tens.

10 is equal to 1 ten.

There's 1 ten.

So 310 is equal to 30 tens, and 1 ten.

310 is made up of 30 tens and an extra 10.

Andeep represents a number using base 10 blocks.

So you can see Andeep's representation there.

"Which bar model shows the same number?" asks Andeep.

So we've got three bar models.

Which bar model shows the same number as the base 10 blocks? Pause the video and try and work it out.

And welcome back, let's see how you got on.

Which bar model shows the same number as the base 10 blocks? Where the base 10 blocks show 400 and three extra tens or 40 tens and three extra tens.

40 tens and 3 tens = 430.

Well done if you got that one correct.

Sophia finds the missing number from the bar models.

What number is equal to the amount of tens? So the first bar model, we've got 20 tens and 9 tens.

What three digit number is equal to 20 tens and 9 tens? 20 tens are equal to 200.

9 tens are equal to 90.

What is 290? 29 tens equals 290, so the answer is 290.

Let's look at the next bar model.

So the next bar model has 40 tens and 4 tens.

40 + 4 = 44.

So altogether there are 44 tens and that equals 440.

And let's look at one more bar model.

So the last bar model, there are 50 tens and 6 tens.

So altogether there are 56 tens.

And 56 tens = 560.

What number is missing from the bar model? What number is equal to the amount of tens? So the bar model shows 30 tens and 8 tens.

What number is missing? "What three digit number is equal to 30 tens = 8 tens?" asks Andeep.

Pause the video and see if you can work out the answer.

And welcome back.

Let's see if you are right.

So 30 + 8 = 38, 38 tens.

And 38 tens = 380.

So the missing three digit number was 380.

Very well done if you got that correct.

Sophia completes the bar models.

What amount is missing from each bar model? So our first bar model, we have the sum, we have the three digit number, which is 520.

And 520 is made out of 50 tens, and what other number? 50 tens are equal to 500.

520 is equal to 50 tens, add another 2 tens.

So 52 tens equals 520, so the missing amount is 2 tens.

Let's look at the next one, 390.

390 is made out of nine tens, and what other amount of tens? Oh, 39 tens equals 390.

So 390 is made out of 9 tens and 30 tens.

30 tens + 9 tens = 390.

And our last bar model.

So the three digit number is 710.

And 710 is made out of 1 ten and how many more tens? Well, the 1 ten makes the 10 part of 710, how many tens do you need to make 700? So 71 tens altogether makes 710.

So 70 tens is the missing part.

70 tens + 1 ten = 710.

Complete the bar model.

What amount is missing? So the three digit number is 490 and one of the parts is 9 tens, what's the other part? Pause the video, and see if you can work out the answer.

Welcome back.

Let's see how you got done.

So 490, how many tens altogether is 490? 49 tens = 490.

So how many more tens would you need? You would need 40 tens.

And again, very well done if you've got the right answer.

And let's move on to task A.

So part one of task A, you've got to say what numbers are represented? So how many tens are there altogether? And that number of tens, what is it equal to? What three digit number would it make? And part two, which three digit number is equal to the number of tens? So you've got to work out how many tens there are, and then work out what three digit number is equal to that number of tens.

And then complete the equation underneath.

The number of tens is equal to what three digit number? And finally, part three of task A, find the missing numbers.

So for these, you've got to find the missing part.

And again, complete the equation saying the number of tens and what three digit number is equal to that number of tens.

So pause the video and have a go at task A.

And welcome back.

And let's look at some of those answers.

Let's start off by looking at number one.

So one A, altogether there are 33 tens.

And 33 tens = 330.

Part two of task A, which three digit number is equal to the number of tens? So 20 tens and 6 tens is equal to 260.

26 tens equals 260.

And for part three you had to find the missing numbers.

So that first missing number was 3 tens and 53 tens equals 530.

Very well done if you managed to get onto the third part of task A.

And let's look at the second part of our lesson.

So the second part of our lesson is using multiplication to show a number of tens.

Three digit multiples of 10 can be written as a multiplication equation.

"How many tens are represented by the base 10 blocks?" asks Sophia.

How many tens are there? The base 10 blocks represent 20 lots of 10.

20 lots of 10 equals 200.

Is there a symbol that means lots of? I expect you know a symbol that means lots of, can you remember what it is? This symbol means multiply or lots of, and it looks like a little X or a cross.

And sometimes we call it times and sometimes we call it multiply.

I can use a multiplication equation to show the number of tens, says Sophia.

So again, there were 20 tens.

20 lots of 10 equals 200.

20 multiplied by 10 equals 200, that multiply symbol just means lots of.

So Andeep's got another one we're going to be looking at.

"So, how could I write this multiple of 10 as a multiplication equation?" asks Andeep.

So this time, how many lots of 10 are there? Well there were 300, how many lots of 10 would that be? It would be 30 lots of 10.

30 lots of 10 equals 300.

And we could also write that as 30 multiplied by 10 equals 300.

Sophia uses multiplication equations to describe the number of tens.

"What multiplication equations do I write?" asks Sophia.

So what multiplication equation which we write for that first base 10 block representation.

There are 23 lots of 10.

10 lots of 10, and 10 lots of 10, and three lots of 10.

23 lots of 10 equals 230.

What number multiplied by 10 equals 230? Well be 23.

There are 23 tens altogether.

23 multiplied by 10 equals 230.

What about this representation here? What multiplication equation would Sophia write to describe it? How many lots of 10 are there altogether? There are 10 lots of 10 and 10 lots of 10, 10 lots of 10, and then five lots of 10.

Altogether there are 35 lots of 10 And 35 lots of 10 are equal to 350.

So what multiplication equation would Sophia write? She would write 35 multiplied by 10 equals 350.

Match the base 10 blocks to the correct equation.

So we've got three representations there, made out of base 10 blocks.

And on the other side we've got three equations.

Can you match the correct base 10 block representation to the correct equation? Pause the video and see if you can match them up.

Welcome back, let's have a look, see how you got on.

The very, very top one is 23 multiplied by 10 equals 230.

The one in the middle is 33 multiplied by 10 equals 330, which means that representation at the bottom is 32 multiplied by 10 equals 320.

Very well done if you've got all three of those correct.

Andeep represents a number of tens.

"How many tens are represented by the hundreds frames?" asks Andeep.

So what number has Andeep represented there? "There are 37 tens altogether," says Sophia.

37 multiplied by 10 equals 370.

So that altogether there are 37 lots of 10.

37 multiplied by 10 equals 370.

Andeep represents another number of tens.

How many tens are represented by the hundreds frames? How many do you think there are this time? "There are 41 tens altogether," says Sophia.

And how would you write that as a multiplication equation? 41 multiplied by 10 equals 410.

There are 41 lots of 10 altogether and that is equal to 410.

And here's one to try on your own, how many tens are represented by the hundreds frames? Use a multiplication equation to describe them.

So pause the video, can you work out what multiplication equation would describe those hundreds frames? And welcome back.

Let's see if you've got the right answer.

So how many tens are there altogether? There are 38.

38 multiplied by 10 equals 380.

There are 38 lots of 10 altogether.

Very well done if you've got the right answer.

Andeep completes these multiplication equations.

"I'm going to write the multiple of 10 to complete the equations," says Andeep.

So the first one says something multiplied by 10 equals 270.

How many tens would you need to equal 270? The answer would be 27.

27 multiplied by 10 equals 270.

Let's look at the next one.

Something multiplied by 10 equals 340.

How many tens would you need this time? You would need 34.

34 multiplied by 10 equals 340.

And the last one, 10 multiplied by what number equals 430? How many tens would you need this time? You would need 43.

10 multiplied by 43 equals 430.

Sophia completes these multiplication equations.

What multiple of 10 do these equations equal? So 29 multiplied by 10 equals what three digit number? It's going to be a multiple of 10.

What are 29 lots of 10? The answer would be 290.

What would 10 multiplied by 54 be? So what would 54 lots of 10 be? The answer would be 540.

10 multiplied by 54 equals 540.

And then what number equals 63 multiplied by 10? So it's still an equation, but this time you've got the three digit number appearing first in the equation.

So the three digit number is 630.

630 equals 63 multiplied by 10.

Complete these multiplication equations.

"What are the missing numbers?" says Sophia.

So there are two multiplication equations.

Can you work out what numbers are missing from both of them? Pause the video and see if you can answer both questions.

And welcome back.

Let's see how you got on.

So that first one, something multiplied by 10 equals 470.

The answer would be 47.

47 multiplied by 10 equals 470.

And the second missing number would be 550.

550 equals 55 multiplied by 10.

Very well done if you've got both correct.

Sophia put seven counters on the place value grid.

She only uses them as hundreds or tens.

So she doesn't use any counters to represent the ones.

My number has 5 hundreds and 2 tens.

So she's used seven counters, she's put five of them in the hundreds and two of them in the tens.

Sophia completes the multiplication equation.

So what three digit number is equal to a number of tens? How many tens there altogether? Let's start off with a three digit number.

There are 5 hundreds and 2 tens, so the answer would be 520.

And 520 is equal to 52 multiplied by 10.

And here's one to try on your own.

So Andeep moves one counter to represent a different multiple of 10.

You see there, he's just moved one of the counters, he's moved it from the tens into the hundreds.

"My number has 6 hundreds and 1 ten," says Andeep.

What multiplication equation represents Andeep's counters.

What calculation should Andeep use to represent his counters? Pause the video and see if you can work out the answer.

And welcome back.

Let's see if you've got the right answer.

Hopefully, you came up with 610 is equal to 61 multiplied by 10.

Altogether Andeep has represented 61 lots of 10, which is equal to 610.

Very well done if you got got that right.

And let's move on to task B.

So the first part of task B, describe the base 10 blocks using a multiplication equation.

Let's look at that first question.

What number multiplied by 10 is equal to 210? Part two of task B.

Complete the multiplication equations.

You can use base 10 blocks or hundreds frames to help you if you've got them.

But can you complete these multiplication equations? So can you find the missing numbers? And sometimes it's the three digit number that's missing, sometimes it's the number that you'll multiplied by 10 is the number that shows the number of tens.

And then finally, part three of task B.

Andeep has nine counters, he uses them as hundreds or tens.

What numbers can I make using the counters as Andeep? Use multiplication equations to show the numbers Andeep can make.

So what three digit number equals a certain number of tens? So see how many different ways you can complete Andeep's challenge.

So pause the video and have a go at task B.

And welcome back, and let's look at those answers.

So for the first part of task B, describe the base 10 blocks using a multiplication equation.

For the first one, it was 21 multiplied by 10 equals 210.

So very well done if you've got those ones correct.

And let's move on to part two of task B.

So complete the multiplication equations.

So A was 39 multiplied by 10 equals 390.

And B was 530 equals 53 multiplied by 10.

So very well done if you've got onto to part two.

And here are the possible answers for part three.

So lots and lots of different answers for this one.

Say for example, you could have put all the counters in the hundreds and you could have ended up with 900 equals 90 multiplied by 10.

Or you could have put all the counters in the tens and you could have had as your answer, 90 equals nine multiplied by 10.

So there's lots and lots of different answers.

So well done if you've got some of those.

And very, very well done if you've got every single one, that is absolutely excellent work.

So very good work in today's lesson, and I hope you're feeling much more confident about using multiplication to show a number of tens.

And let's finish off by looking at our lesson summary.

Base 10 blocks and hundreds frames can represent multiples of 10.

This symbol means multiply or lots of.

Any three digit multiples of 10 can be written as a multiplication equation.

For example, 990 is equal to 99 multiplied by 10.