Lesson video

Hello, I'm Miss Miah and I'm so excited to be a part of your learning journey today.

I hope you enjoy this lesson as much as I do.

In this lesson, you'll be able to use the relationship between the twos, fours, and eight times tables to solve problems. Your keywords are on the screen now, and I'd like you to repeat them after me.

Multiple.

Double, doubling.

Halving.

Great.

Let's move on.

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

To double means to become twice as many or to multiply by two.

Halving means to divide into two equal parts.

So this lesson is all about your twos, fours, and eight times tables.

You are going to be using your knowledge about these table facts and relationship facts to help you solve problems. We've got two lesson cycles here.

Our first lesson cycle is to do with finding the missing number, and our second lesson cycle is to solve problems. So let's begin with our first lesson cycle.

In this lesson you'll meet Andeep and Izzy.

We are first going to have a warmup and we're going to be counting on in multiples of two, which means you're going to be adding two each time starting from zero.

Let's do the countdown and I want you to join in with me.

Three, two, one, zero.

Two, four, six, eight, 10, 12, 14, 16, 18, 20, 22, 24.

Fantastic work.

If you've got all of those correct, good job.

You have just shown me that you can count on in multiples of two.

Let's move on.

Now we're going to be counting on in multiples of four, which means we're going to be adding four each time and we're going to start with zero.

Let's do a countdown.

Are you ready? Three, two, one.

Zero, four, eight, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48.

If you managed to count in your multiples of four and you got all of those correct, fantastic job.

Now let's move on to our eight times tables.

So this time we're going to be counting on in multiples of eight, which means we'll be adding eight each time to zero.

And I'm going to start off with zero again.

Let's do our countdown.

Are you ready? Three, two, one.

Zero, eight, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96.

If you managed to count in eights and you got all of those correct, fantastic work.

Now, Izzy is solving missing number problems. We've got an array here.

It shows eight.

So let's have a look.

This is part of her number problem.

So we've got one group of eight and then it says that that is equal to two groups of four.

So one group of eight is equal to two groups of four and two groups of four is equal to something multiplied by two.

Andeep dropped off my number.

What advice would you give to Izzy? I'd like you to explain your reasoning to your partner.

Now, you may have said something similar to this.

If I know that one times eight is equal to eight, then I know that two times four is equal to eight.

That means four times two is equal to eight because four two times is eight.

And we can see that that's been shown on the array.

We've got two groups of four, or four, two times.

Over to you.

I'd like you to fill in the blank using the array and it's dropped off the number again.

You could pause the video here.

Off you go, click play when you're ready to join us.

So what did you get? You should have got eight groups of two and that's because two groups of eight is equal to four groups of four and eight groups of two.

Izzy is solving missing number problems. Now she's got an equation there.

Four times 10 is equal to eight times which is equal to two times.

Now Andeep's dropped off the numbers again.

Cheeky Andeep, right? So what advice would you give to Izzy? Explain your reasoning to your partner.

Well, you may have said something along these lines.

If I know that four times 10 is equal to 40, then I also know that eight times five is equal to 40.

This is because five groups of eight is equal to 10 groups of four.

And if I know that four times 10 is 40, then I also know that two times 20 is equal to 40.

The missing numbers were five.

So here what we could have done is used the relationship between the four twos, fours and eights.

We know that multiples of two, if you double them, are multiples of four and we know that if you double again, you can also find the multiples of eight.

Over to you.

Find the missing number and I'd like you to show the relationship using an array.

So here your equation is four times six is equal to eight times three, which is equal to two times.

You can pause the video here, click play when you're ready to rejoin us.

So how did you do? Well, if you know that four times six is 24, then you also know that two times 12 is 24.

This is because four groups of six is equal to two groups of 12 and this is how you could have showed it on your array.

Now Izzy is collecting data for science.

A human has two legs and axolotl has four legs and an octopus has eight legs.

Izzy has recorded part of her data based on observations she has made as an aquarium.

These are her recordings so far, so you can see that she's got number of octopus legs as her first column.

Then she's got the number of axolotl legs as her second column and axolotl lot have four legs.

And then her third column are number of human legs and humans have two legs.

And then on the left hand side you can see that she's got one, two, and then a missing number and four.

So she's partially filled out her table.

Izzy says that she can calculate the rest of the data by using what she knows about her twos, fours, and eight times tables.

So she says that if she knows that one group of four is four, then she also knows that one group of two is two because half of four is two.

Now she's looking at the number of axolotl legs compared to the number of octopus legs.

She says that if she knows two groups of four is eight, then she also knows that two groups of eight is 16 and she knows that she has to double eight to 16 because an octopus has double the number of legs compared to an axolotl.

So that means 16 is the missing number there.

Now using your knowledge of the twos, fours, and eights, I'd like you to fill in the blanks.

You can pause the video, here off you go, and click play when you're ready to rejoin us.

So how did you do? Now if three octopuses is 24 legs, then three axolotls is 12 legs because an axolotl has half the number of legs.

If three octopuses is 24 legs, then three humans is six legs because halving twice will give you the number of legs of a human.

Back to you.

Using your knowledge of the twos, fours, and eights, I'd like you to fill in the blanks.

You can pause the video here, click play when you're ready to rejoin us.

So what did you get? If you've got 32, you are correct.

And that's because if four axolotls have 16 legs, then eight octopuses will have 32 legs because an octopus has double the number of legs an axolotl has.

So that means we need to double 16 and doubling 16 gives us 32.

Onto your main task for this lesson cycle.

So you are going to be using your knowledge of the relationship between twos, fours and eights to find the missing numbers.

So let's have a look at the first question.

One times eight is equal to two times four, which is equal to something multiplied by two.

Every number you get for that missing gap must also have the same product as the other two equations.

So I'm going to read you through the other questions now.

Two times eight is equal to something multiplied by four, which is equal to eight times two, three times eight is equal to something multiplied by four, which is equal to 12 times.

Four times is equal to eight times four, which is equal to 16 times two, five times eight is equal to something multiplied by four, which is equal to something multiplied by two.

Now if we look at the right hand side, we can see that there are some equations.

What I'd like you to do is use the relationship between the twos, fours and eights to find the answers for these.

So if you know that six times two is, then you also know that two times three is.

If you know that six times four is, then you know that six times eight is.

Okay? And for question two, you're going to fill in the missing numbers in the chart using your knowledge of the twos, fours, and eights.

You know that an octopus has eight legs an axolotl has four legs and humans have two legs.

Using this information, I would like you to fill out the rest of the chart.

You can pause the video here.

Off you go, good luck.

So how did you do? This is what you should have got for question one.

So one times eight is equal to two times four, which is equal to four times two.

Each time the product was eight and for the second equation your missing number was four.

For the third equation, your missing numbers was six and two.

For your fourth equation, your missing number was eight.

And for the fifth equation, your missing numbers were 10 and 20.

Now, using your relationship of your twos, fours and eights, you should have been able to answer these questions.

So we are going to focus on seven times two, seven times four and seven times eight, and then you can pause the video to mark the rest of your work.

So if you know that seven times two is 14, then you also know that seven times four must be double what seven times two is because one of your factors have doubled.

So seven times four would've been 28, and then seven times eight would've been 56.

And that's because you would've doubled 28 to get 56.

And that's due to the fact that the the factor four has doubled to eight.

So you should have also doubled your product.

And then if we have a look at two times nine, four times nine and eight times nine, well I know I will have to be doubling the product each time because one of the factors is the same, which is nine, and then the other factors have doubled each time.

And then you should have got 18 as your product, 36 as your product and 72, you can pause the video here and mark your work.

So how did you do? If you managed to get all of those correct, well done.

Let's move on.

For question two, this is what you should have got.

So I will read out the missing numbers and you can mark them as I go along.

So for row one, you should have got two legs for humans.

For row two, you should have got 16 legs altogether for the octopuses.

For row three, you should have should have got three.

For row, and then the number of legs for axolotl was 12 and six.

For row four, the missing number of legs was 32 legs altogether for your octopuses.

For row five, you should have had your missing number is five and then your 20 legs altogether for your axolotls, because four times five is 20 and number of human legs would've been 10.

Row six, you should have got 48 as the number of legs for your octopuses and row seven, you should have got 28 and 14 as your missing numbers for number of legs for the axolotls and humans.

Now let's move on to lesson cycle two, which is to solve problems. Now Izzy has baked 16 cupcakes.

How many boxes would she need if one box hold two cupcakes? So I want you to think about what is known, what is unknown, and how you might represent this problem as a bar model.

Well, you know that there are 16 cupcakes altogether and this is our product.

You know that one box holds two cupcakes altogether.

This is a factor.

You do not know how many boxes are needed altogether, and that's your missing factor.

So that means that equation that you are calculating is two, which is how many cupcakes will fit in one box multiplied by how many boxes we need, which gives you 16 cupcakes altogether.

So you are calculating the missing factor.

Now, you might have represented the problem like this as a bar model.

So you know that 16 is your product, is the whole, one box is two cupcakes, and then you're figuring out how many number of boxes you need.

So that is known and that's your unknown.

And again, the equation that you are calculating is two multiply by something gives you 16.

The answer can also be calculated using division.

So 16 divided by two will give you the amount of boxes you need for the cupcakes.

So two groups of eight is equal to 16.

So that means Izzy needs eight boxes.

Over to you.

What equation is needed to solve this question? So Izzy has baked 32 cupcakes, how many boxes would she need if one box holds four cupcakes? You could pause the video here and click play when you're ready.

So what did you get? Well, you know that there are 32 cupcakes altogether.

That's your product.

So you also know that one box holds four cupcakes.

That's one of your factors.

You do not know how many boxes are needed in total, which is your other factor.

That's your missing factor.

So the equation is four times something is equal to 32.

So we know that four eight times or eight four times is 32.

So the missing factor was eight.

Over to you.

I'd like you to represent this question as a bar model.

If Izzy has baked 32 cupcakes, how many boxes would she need if one box holds four cupcakes? You can pause the video here.

Off you go.

So what did you get? Well, this is what you should have got.

32 is known.

So that's our product.

That's how many cupcakes we have altogether.

We know that one box holds four cupcakes, so the value of one box is four.

We need to now know how many number of boxes we need.

So that is the unknown.

Let's move on.

A fruit stall is having a sale.

It sells watermelons in crates of four pairs.

How many watermelons are there in one crate? So here we've got one crate.

There's four pairs of watermelons there.

So one pair of watermelons is equal to two, that's one times two is two.

Double one pair of watermelons is equal to four.

So two times two equals four.

Double two pairs of watermelons is equal to eight.

So four times two is eight.

So that means there are eight watermelons in one crate.

So now we need to calculate how many watermelons there are in three crates.

So if one crate has eight watermelons, that's one group of eight, that's one times eight, three crates of eight is three times eight.

So three times eight is equal to 24.

There are 24 watermelons altogether.

Over to you.

How many watermelons are there in four crates? You could pause the video here, off you go and then click play when you're ready to join us.

So what did you get? Well, eight four times is 32, so you should have got 32 watermelons altogether.

Onto our main task for this lesson cycle.

For question one, you're going to be completing the following questions and writing a multiplication equation for each.

Izzy has baked 24 cupcakes, how many boxes would she need if one box holds two cakes, if one box holds four cakes, and if one box holds eight cakes? For question two, a fruit stall is having a sale It sells cherries in boxes of four pairs.

So how many cherries are there in one pack? How many cherries are they going to be in three packs? And if Izzy buys 40 cherries, how many packs is this and how many pairs of cherries is this? You can pause the video here.

Off you go.

Good luck and click play when you're ready to rejoin us.

So how did you do? So for question one, one box holds two cakes.

You should have got 12 boxes because 12 two times is 24.

So 12 boxes with two cupcakes will give you 24 cupcakes altogether.

Now if one box holds four cakes, you need six boxes.

Lastly, one box holds eight cakes.

So that means we need three boxes because eight times three is 24.

For question two, you should have got eight cherries, and that's because two times four is eight.

Now in three packs multiply three by eight to get 24 cherries.

Now, if Izzy has bought 40 cherries, in order to calculate how many packs this is, we need to divide our whole, which is 40 by eight, and we end up with five packs of cherries.

And we could check that again because if we multiply eight by five, that also gives us 40, and that's how many she purchased.

And lastly, this is 20 pairs of cherries because we need to divide 40 by two because that's how many pairs of cherries we have.

So 40 divided by two is 20 pairs of cherries.

Well done.

We've made it to the end of the lesson and now we're going to summarise our learning.

So now you should hopefully understand that if you double the multiples of two, you get the multiples of four.

If you double the multiples of four, you get the multiples of eight.

If you double the multiples of two and double again, you get the multiples of eight, and then you can use this knowledge to solve problems. I really enjoyed this lesson and I hope you enjoyed it too.

I look forward to seeing you in the next one.