Lesson video

Hi everyone, I'm Mrs Crane and welcome to today's lesson.

Today we're going to be looking at part of a unit on multiplication and division, and our objective today, is going to be to learn how to identify multiples of 2, 3, 4, 5, and 10, by applying our knowledge of all of our known times tables.

For this lesson, you'll need a pencil and some paper, please pause the video now, to go and get these things if you haven't gotten them already.

Okay, I thought I'd start the lesson with a bit of a did-you-know fact: did you know, that snails can sleep up to 3 years? It does seem like a very long time doesn't it? Right then let's have a look at today's agenda.

So today, as I said before, we're going to be learning how to identify multiples of the 2, 3, 4, 5, and 10 times table.

We're going to start with a quiz to test your knowledge.

Then we'll look at the star words, then we're going to look at times tables and how we can identify multiples.

Then it'll be time for your talk tasks.

Then we'll develop our understanding of multiples by using arrays, working systematically, and looking at the project.

And finally, there'll be a quiz to see what you've remembered.

Please pause the video now to have a go at today's starter quiz.

Okay then, now we're going to do the star words, so we'll do my turn your turn: Multiple.

Multiply.

Groups.

Product.

Equal.

Brilliant.

Alright, then let's look at today's new learning.

So we know the 2, 3, 4, 5, and 10 times tables, which times tables do you think are similar and why? 5 seconds thinking time, which ones are similar and why? Okay let's have a look then.

So, I know that the 5 and the 10 times table are similar because I know that some numbers in my 5 times table, like 10 and 20, are also in my 10 times table.

I also know that my 2 and my 10 times table are similar, because I know that numbers in my 2 times table are in my 10 times table, like 10 and 20.

Let's explore a little bit further then.

So, what multiples appear in the 2, 5, and the 10 times table? Before we can answer that question, we need to know what a multiple is.

So let's look back at star words.

Star word multiple means the results when you multiply a number by another number, okay? So, to find out the multiples that appear in our 2, 5 and 10 times table, let's have a look at our 2, 5 and 10 times table.

Here we go, we've got multiples of 2 here, and multiples of 5 here, and multiples of 10 here.

What we're going to use is some skip counting to read these out altogether.

So we're going to skip count in our 2s up to 24.

Go! 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24.

Now what we're going to do is skip count in our 5s, let's go! 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60.

Brilliant.

And lastly, we're going to skip count in our 10s, ready? 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120.

Brilliant, I'm really impressed.

So, we've read out the multiples of 2, 5, and 10, now we've got to find the multiples that are multiples of all 2, 5 and 10.

I want you to have 5 seconds thinking time, which numbers on our screen are multiples of 10, 5, and 10.

Okay.

Let's work systematically then, let's work through our times tables and start with our 2s.

Now I know that 2, 4, 6, and 8 aren't in our 5 and 10 times table, but I do know that 10 is.

I also know that 20 is.

I know that 12, 14, 16, and 18 aren't in our 5s or 10s, if I quickly look at them, I can see they're not in that, And I know that those numbers aren't multiples of 5 and 10.

Let's have a look then at our 5 times tables.

You'll notice 10, 20, 30, 40, 50, 60 up.

Now they're all multiples of 2 because you can see here our multiples of 2 that are multiples of 5 and 10 are all multiples of 10.

We can see here that 5 and 15 aren't circled.

Why are they not circled? Well done.

They're not multiples of 10 or 5, they don't appear in our 5.

our 2 sorry.

They don't appear in our 2 or our 10 times tables so that we have to just choose the numbers that appear in all three times tables.

Multiples of 10 then.

All of those numbers are circled.

Why are they all circled? That's because they're all multiples of 5, and they're all multiples of 2 as well.

What we're going to do now is have a closer look at the number 20.

So we're going to look at some different arrays here.

You can see this array shows 5, four times.

We've got four groups of 5 is equal to 20.

You can see here, the number 10, two times.

10 times 2 is equal to 20.

You can see also we've got the same arrays, but we've got them switched around, because we can use the commutative law in multiplication to move around the 2 numbers before our product, our product being the results when you multiply two or more numbers together.

So here we've got 2 times by 10 is 20, and 5 times by 4 is 20.

20 being shown in 4 different ways.

Therefore we know 4, 5, 10, and 2 are all multiples of 20.

Now, is 20 multiple of any other number? Is 20 a multiple of 6? Why or why not? And in order to do this I need to make an array using my 6s.

So I'm going to do 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20.

I've counted out 20 counters and I've arranged them into groups of 6.

Have I arranged them equally? No I haven't, I've got 2 remaining.

That tells me that 20 is not a multiple of 6 because it doesn't equally divide by 6.

If I counted up in my 6 times tables, I'd go 6, 12, 18, 24, but do I have 24 there? No I don't, I just have 26, not a multiple of 6, and we can clearly see that when we look at our array.

So arrays are really helpful for when we're looking at finding multiples of different numbers.

Now it's time for your talk task.

So, today for your talk task I'd like you to do is select a number from this box here, from this grid, and create an array for that number.

Explore whether the number is a multiple of 2, 3, 4, 5, or 10; is the number a multiple of more than one number? Then choose just one of these, And you're going to work through these numbers here to see if they're multiples of them.

You could do it by drawing the arrays just like I've just done.

Remember you can use your say it out loud here to help you, please pause the video now to have a go at today's talk task.

Okay, what we're going to do now and as part of our develop learning is look through one of these examples.

So we're going to take 21 from our number cards here, and we're going to explore whether it's a multiple of 2 or not firstly, we're going to work through them systematically.

To work systematically just means working like a system.

So we worked through them one at a time to know that we've checked them all.

If I had just said, Oh, I'm going to check 4, and then I'm going to get 10, then I'm going to check 2, I might forget to check 3 and 5 as well.

So if I've worked systematically, it means I can work through them one at a time with a system to the way that I'm working.

So then, 21.

I'm going to draw it out using my arrays, using groups of two, so 1, 2; 3, 4; 5, 6; 7, 8; 9, 10; 11, 12; 13, 14; 15, 16; 17, 18; 19, 20; 21.

Is it shared equally when it's shared into groups of 2? No it's not, because I have one remaining here.

So I can say 21 is not a multiple of 2.

And I can write it down.

Next then we're going to look at, is it multiple of 3? So this time I've got my array, I've got 3.

I'm going to skip count this time: 6; 9; 12; 15; 18; 21.

This time I can say 21 is a multiple of 3.

It's also the product of 3.

And then if I count how many groups of 3 I've got, I can work out the number, so: 1, 2, 3, 4, 5, 6, 7.

So I can say 21 is the production of 3 and 7, but it's also the product of 7 and 3, because remember what I said earlier about the commutativity I can move my 7 on my 3 around.

Let's have a look then at the number 4.

Again, I'm going to skip count this time.

4; You can join in; 8; 12; 16; 20; 21.

Has it been shared equally? No it hasn't because I got my one here.

So I need to say 21 is not a multiple of 4.

Let's have a look then at 5.

Again I'm going to skip count: 5; 10; 15; 20; 1.

Is it shared equally? No it's not.

So I can say 21 is not a multiple of 5.

And lastly let's look at 10.

10; 20; 1.

Has it been shared equally? No, it hasn't, I've got one remaining here, so I can say 21 is not a multiple of 10.

Is the number a multiple of more than one number? Well, we know that it's the multiple of 7 and 3, But look, also a multiple of, look here, my array showing 21, let's count them: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, showing it once.

So I could also say that 21 is a multiple of 1 and 21 as well as being a multiple of 3 and 7.

Right then it's now time for your independent task today.

What I'd like you to do please is select a number and create an array for that number.

So you've got your 4 numbers here and you're going to create an array for them.

Explore whether the number is a multiple of 2, 3, 4, 5 or 10, and then write down your findings using the number sentence examples below.

So you've got the examples here, something is a multiple of, is not a multiple of, is a product of.

and.

Select one of these cards and use these sentences here to help.

Please pause the video now to complete your task.

Okay, welcome back.

What we'll do now is have a look through the answers together then.

So, we're going to look at 16 first.

16 is a multiple of 2 and 4.

It's not a multiple of 3, 5, 10, 16 is a product of 2 times by 8, and 4 times by 4.

There's 2 answers to this box here.

Okay, then let's take a look at the number 24.

So the number 24 is a multiple of 2, 3 and 4.

It's not a multiple of 5 or 10 because it's not in the 5 or 10 times table.

24 is a product of 2 and 12, of 4 and 6, and 3 and 8.

Number 18.

18 is a multiple of 2 and 3, 18 is not a multiple of 4, 5, or 10, and 18 is a product of 2 times by 9, and 3 times by 6.

And lastly 30 is a multiple of 2, 3, 5, and 10.

It's not a multiple of 4, and it is the product of 2 times by 15, 3 times by 10, 5 times by 7 and 10 times by 3.

Well done for one of your hard work today, I've been really, really impressed.

Please pause the video now to complete the final quiz and answer the last few questions.

Thank you.

And hopefully we'll see you again soon.

Bye bye.