Lesson video

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

Today we're going to be looking at a unit in multiplication and division, and today's session will be based on arrays that are for the multiplication tables of three and four.

For this lesson, you will need a pencil, and some paper.

Please pause this video to go and get these things if you haven't got them already.

Okay, I thought I'd start today with a bit of a riddle.

When things go wrong, what can you always count on? When things go wrong, what can you always count on? Your fingers.

Right, let's get started then.

So, our agenda for the lesson.

Today, as I said at the beginning, we're going to be learning how to describe and interpret arrays for the multiplication tables of three and four.

I'm going to start with a quiz to test your knowledge, then we'll look at today's star words, then we're going to see how multiplication dots.

First of all, we're going to find out what they are, and we're going to find out how we can use them to show arrays.

Then there'll be a chance for a talk task, then we're going to develop our understanding of arrays and how we can use them to help us answer equations.

Then it will be time for you to do your independent task and we'll review the answer together.

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

Please pause the video now to complete your starter quiz.

Okay.

So, let's have a go at today's star words then.

We're going to use my turn, your turn for the star words.

So multiply.

Divide.

Array.

Part.

Whole.

Groups.

Brilliant, everyone.

Let's have a look then at our new learning today.

So, we're going to look, firstly, at the dot multiplication table of three.

So here we can see here's our dot multiplication table of three.

Now, along the top, you can see one, two, three.

And down here, you can see different numbers, all the way up from one 'til 12 and our dots for three.

Now, I want to firstly use my dot multiplication table of three to find two groups of three.

So I'm going to just put this here just to block it off, so I know I don't need to look at this part or underneath here.

Just a bit like using a ruler really, to help you concentrate on what's above it.

So, I can see here, I have got one, two, groups of three.

Here are my dots.

If I had to write that as an equation.

I would be writing, three times two or two times three is equal to six.

We're going to look at what I mean by saying three times two or two times three, now.

Cause what I'm about to do, is I'm going to take this away.

You can't see it.

We're going to turn it.

So you can see it like this.

I'm going to put my little box over it again.

It's the same thing.

So I've looked this time, at my two groups of three.

I can see this time there's one- two groups down here of three.

And this time, I could write it, as three times by two is equal to six.

So, I could write it either way.

And I could show it either way.

And it still gives me the same answer.

So, if I had to think, about what my whole would be and what my parts would be, here you can see I've got two parts.

What number is going to go in these boxes do you think? Have a little think.

Well done to those of you that said three.

Because I did.

I had two groups of three.

So, my parts are three and three.

My parts are two and they have a value of three each.

Sorry And my whole, therefore, is six, because, in total, I have six dots.

Let's have a look, then, at the next one.

Three groups of three.

Again, I'm going to put my little box in so that we don't have to look at the wrong numbers.

So in goes my box and I can see here, clearly, three groups of three.

So my equation, would be three times three is equal to nine.

Because I know three times three is equal to nine, I could use my skip counting.

I could count them, but I don't have to.

Just like with arrays, we don't have to count them, we can use out skip counting to help us.

Now, let's see what happens if we turn, and take this away again, and turn it on it's side again.

And replace my little box again.

Again you can see three rows with three in each one.

Will my equation look different? No it won't, because I could change it to three times three, but those are the same two numbers.

So, this time, here's my part-part-whole model.

My whole we need to know and we've got three parts this time, each with a value of? Three, well done! Because, look here, I've got one, two, three parts and they all have a value of three.

In total then, my whole, it was nine, so my whole has to be? Nine.

Next one for the dot multiplication table of three, we're going to look at four groups of three.

So, let's put into place our box.

Fantastic.

You can now see one, two, three, four groups of three here.

So my multiplication would be four groups, or times, three is equal to 12.

So I can use my skip counting.

Three, six, nine, 12 to know there's 12 there.

Let's see then, what happens this time, if I take it away and turn it.

There's that guy.

There's that.

I've put back into place my box.

This time, I can see three rows, yeah three rows, sorry, and each row has one, two, three, four in it.

So if I said three times by four is equal to 12, I've got the same numbers, but the other way around.

Just flipped it on it's side to give me the other way around.

Let's have a look, then, at our part-part-whole.

So, we don't at the moment know what our whole is, we know we've got one, two, three, four parts and each of those parts is equal to three.

So we're going to have three in each of these boxes and then our whole, we know was 12.

Fantastic! So I put my 12 in here.

Now, we're going to look at the dot multiplication table of four.

Looks very similar to the dot multiplication table of three, except we've got an extra column here.

Two groups of four.

So, I'm going to put my box in here, so that I'm just looking at my first two rows.

There we go.

I can see here I've got two groups of four.

So if I have to write it down, I would write four times two is equal to eight.

So I've got my four, right.

Let's see what happens, then, when I turn it.

Take it away, and here we go.

This is the same dot multiplication table, it's just been turned the other way around.

So, now, I can see I've got twos, four times.

So my multiplication would be two times four, the same answer.

It gives me an eight.

Again, I've got my part-part-whole, so at the moment, I'm thinking that my two groups of four in these two boxes, they're going to be fours.

And I know, that two groups of four is equal to, bang, eight.

So my whole is eight.

This time I've got three groups of four.

Let's put in our box.

Here we go, it's covering it over.

We can see, we've got one, two, three groups of four.

And we know that that gives us 12.

Turn it.

Three groups of four is equal to 12 here.

Turn our dot multiplication table again.

We can see it here, three groups of four.

We just turned it the other way around, so this time it's going to be three times by four is equal to 12.

And here, we've put it in already, we have one, two, three parts, each with a value of four and our whole is 12.

Last one we're going to look at, then, is four groups of four.

So, here we have our dot multiplication table.

Let's put in our box, so we can see really clearly.

Here it is.

So here's our four groups of four here.

Four times four is 16.

If I turn it, would I be able to write a different equation? Have a think.

Think back to what happened when we had three times by three.

Let's find out, if we turn it, will it give us a different equation? Put our box in.

We've still got four in each row and four in each column.

So, it won't give us a different equation, it will stick with the same equation.

Now I know I have four groups of four in each, so my parts, there are four of them and they each have a value of four.

And my whole is, therefore, 16.

Right then, it's time for today's talk task.

What I would like you to do for today's talk task is match these equations with the correct arrays.

So your equations are here, your arrays are here.

You've also got to say it out loud so something multiplied by is equal to There are rows of There are altogether.

Three sixes are equal to six threes.

We will go through the answers together at the end of it.

So I'd like you to match the equations with the correct arrays.

You don't have to put in the product or the answer.

You're just looking at the array that matches with the correct equation.

Pause the video now to have a go at today's talk task.

Okay, let's have a look then.

Start here with three times by six.

So if I look at the different arrays over here, I can see that three times by six, I can see I've got three, one, two, three, four, five, six, times so this equation matches with this array.

I'm going to get rid of the arrows just because it gets a bit confusing.

So now we're going to look at four time by two.

Four times by two, I can see here I've got four and I've got four twice.

So the correct array for this one is here.

Five times by three, my next equation.

And I can see here, I've got one, two, three, four, five, here and I've got it one, two, three, times.

Four times by seven, I'm going to do next.

I can see here, I've got four down my column, and I've got it one, two, three, four, five, six, seven times.

Three times by nine, then.

I'm looking for threes or a nine, I can see here, oh and I can also see here, I've got threes.

Let's check.

One, two, three, four, five, six, seven, eight, nine times.

And lastly, I've got six times by four.

I can see here, I've got one, two, three, four, and I've got it one, two, three, four, five, six times.

Well done, everyone! Let's have a look, then, at today's develop learning.

What equation can we write for this question? Let's have a look at the question.

There are three cartons of milk in each box.

How many cartons would there be in eight boxes then? We could do three multiplied by eight, because I know there's three cartons of milk and there are eight boxes.

How many parts are there, then? Well, there are eight parts.

Each of them have a value of three.

Can we draw and array to help show our question? So let's have a look.

I've drawn some arrays here.

You can see, I've got one, two, three and I've got it one, two, three, four, five, six, seven, eight times.

I could show that array in a different way.

I could show it like this.

Again, I've got three.

This time I've got it one, two, three, four, five, six, seven, eight times.

There's different ways of drawing the same equation.

Have a look then, at the next part.

What equation could we write for this question? There are nine sheep in a field, how many legs are there altogether? Now, I know there are four legs on each sheep and there are nine of them.

So I need to do four multiplied by nine.

I've got nine parts, but each part has a value of four.

So each sheep has a value of four.

Can we draw and array to show the question, then? Yes we can.

Again we can draw it in two ways.

We can show that we've got four, nine times.

Here's our one, two, three, four.

And we've got it nine times, is the count down here.

We could also show that we've got nine four times.

You start here one, two, three, four and we can count across here, so we can see one, two, three, four, five, six, seven, eight, nine times.

Absolutely.

Now it's time for your independent task.

So, there's a few different questions today in the independent task.

What I'd like you to do is read the question and use the pictures to help you.

You can work out the answer and the equation.

Here and here.

You then have got, here, some arrays.

What I'd like you to do is use these arrays to help you write the multiplication equation and the answers.

My challenge is: Is there another way you could write your equation Thinking about what we just talked about.

And lastly, I'd like you to draw and array that shows the following equations and then answer them.

Please pause the video now to complete your task.

Okay, let's have a look then at the answers.

So, we'll start with this question here.

There are six cows in a field.

How many legs do the six cows have altogether? Remember each cow has four legs.

So, my equation would be six multiplied by four.

And my answer would be 24 or my equation could be four multiplied by six.

That is also correct if you've got the answer 24.

One rhinoceros has three horns.

How many horns with seven rhinoceroses have? Seven, cause I've got seven rhinoceroses that was a tricky word to say and each one has three horns.

So I've got seven times by three and it's going to give me the answer of 21.

Next then.

Using the arrays, write the multiplication equation and the answers.

So, start here, we've got three multiplied by eight.

So you can see three, and you can see it eight times.

And the answer is 24.

And here we've got four multiplied by six and you can see our answer is 24.

There is another way you could write each equation.

You could write eight multiplied by three equals 24 and you could write six multiplied by four is equal to 24 here.

Lastly then, draw an array that shows the following equations and answer them.

So I've drawn my arrays here.

You can see eight multiplied by four, here's my four, and here is one, two, three, four, five, six, seven, eight.

My answer, then, excuse me, is 32.

And lastly, three multiplied by nine.

You can see my array is here.

Here's three, and here is it one, two, three, four, five, six, seven, eight, nine times.

And the answer is 27.

Well done everyone for working really really hard today.

I've been really impressed.

Please pause the video now to have a go at the final quiz and answer the last few questions and hopefully I'll see you again soon.

Thank you and goodbye.