Lesson video

Hello everyone, and welcome to math with Ms. Dobrowolski.

Today we'll be comparing measures of length and volume.

Let's have a look at our lesson agenda.

First, we'll be looking at representations of difference, then you'll have your talk task, then we'll be looking at understanding difference, and finally, you'll be ready for your independent task.

For this lesson you will need a pencil and notebook.

If you don't have these items, pause the video now and go get them.

Super, so let's get started.

What I would like for you to do is to draw the jumps to find the difference between the circled numbers.

So for example on number one I had one and six circled.

So I'm going to draw the jumps between them.

Watch me.

One, two, three, four, five.

I drew five jumps.

So the difference between one and six is five.

Your turn, pause the video and complete the jumps.

Resume the video when you're ready.

Super job everyone.

So, hopefully you counted the jumps, and in number two, you should have drawn five jumps because the difference between nine and four is, nine and 14 is five.

For number three again, you draw five jumps because the difference between three and eight is five.

And for number four, again you should have drawn five jumps because the difference between 15 and 20 is five.

So what did you notice? Hopefully you realised that there was a pattern here.

Between each of the jumps you had, between each of the numbers, you had five jumps.

Well, what other numbers would fit the pattern? Now for example, you could start at zero and make five jumps to the number five, because the difference between zero and five is five.

The same would have worked with oh, lots of different combinations, seven, eight, nine, 10, 11, 12.

There's five jumps between seven and 12, eight and 13, and so on and so forth.

So what we're doing today is finding the difference between two numbers.

Now, here we have some children playing a game, and the children wanted to see who could throw the beanbag the furthest.

So there was a team who threw a red beanbag and a team who threw a blue beanbag.

And they measured their throws in metres.

So it looks like the blue beanbag was thrown one, two metres and the red beanbag was thrown one, two, three, four, five metres.

What is the distance between the blue beanbag and the redbean bag? Let's take a look.

Now, we could represent the difference using cubes.

So we had the blue being thrown two metres and the red being thrown five metres.

So let's have a look at how we can represent that with cubes.

So, we can see that both teams threw the beanbag two metres at least, so the blue beanbag was thrown two metres and the red beanbag was thrown five metres, which is two plus one, two, three.

So they threw three more.

The first two metres are the same, the difference is the three metres more that the red beanbag was thrown.

We can also represent this on a number line.

So I know that I will circle the number two, because that is how far the blue beanbag was thrown.

And I will circle five because that is how many metres the red beanbag was thrown.

And now I'm going to jump from two to five and I will count my jumps.

The difference between two and five is the difference between the blue bag and the, the blue beanbag and the red beanbag.

So, one, two, three, I make three jumps of one to get from two to five.

So the difference between two and five is three.

As you can see in our cubes, the difference between the blue and the red beanbag was three metres.

And we just represent it the same way on a number line, we jump from two to five and the difference between them or the number of jumps is three.

So I could have looked at this two ways.

I could say that two plus the number of jumps I need to get to five.

So for example, two plus three is equal to five, so the difference between two and five is three.

Or I could subtract what they have in common.

So I know that the red beanbag and the blue beanbag had two metres in common, but the red beanbag was thrown five metres.

So I can start with two, five, I can start with five and subtract two, which is equal to three metres.

So the difference between five and two is equal to three.

For your talk task, I would like you to use the distance in metres from the start line is each beanbag to find the difference between them.

So for example, I'll do the first one.

I want to know the difference between A and B.

So, I'll say this.

Beanbag A was thrown three metres and beanbag B was thrown five metres.

So I will count up from three to five on the number line.

One, two, that means the difference is? The difference is two, because three plus one, two is equal to five.

So the difference between them is two.

Now, pause the video, find the difference for the other two on this table, and then resume the video when you're ready so we can go over the answers.

Great job, everyone.

So for B and C, you should have seen that the difference between five and seven is two.

Because you would start at five and count up to seven, one, two.

And the difference between A and C, you would start at three and count up to seven.

So the difference is one, two, three, four, super job.

Now, these children were playing another game.

And this time they wanted to see who could fill up the most units within two minutes.

So what is the difference between team A's volume and team B's volume? You see each time they filled up, they filled up one unit, so what's the difference between the volume of team A and team B's volume? Well, we can see that team A was able to fill up three units and team B was able to fill up seven units.

So now we need to find the difference between three and seven.

So, we can see that both teams filled up three units, the difference was from three to seven.

So let's count how many units that was.

One, two, three, four, so team B was able to fill up four more units.

That means the difference is four, four units.

Again, both teams transferred the first three units, but team B was able to transfer another four.

So that's the difference, four units.

Now, we can also represent this using our cubes.

Remember, both teams were able to transfer three units, so both teams have three blue blocks, but team B was able to transfer four more.

So because they were able to transfer four more units, they had a total of seven units.

The difference between seven and three is equal to four.

We can also do this on a number line.

We know that each team transferred three units.

So again, we'll start at three and we have to count all the way till seven, because that's how many team B was able to transfer.

One, two, three, four.

The difference is four jumps, so the difference is four units.

That must mean when we count on from three, we add three plus four, which is equal to seven.

Or we can do the opposite and subtract what they have in common, which is three.

So seven minus three is equal to four.

So four again, is the difference.

Now, for your independent task I would like you to answer the following questions.

For A through E, I want you to tick the statements that are true, and for E, you'll need to use the children's clues to figure out how much team E's volume was equal to, how much you should colour in.

So I'll do the first one.

Let's see, the difference between team A and team C's volume is two units.

Is that true? Well, team A was able to transfer three units and team C was able to transfer five units.

Let's see, is the difference between three and five, two? Yes, it is.

Because three plus two is equal to five.

So I take that because I know it is true.

If it is not true, do not take it.

Again, pause the video, complete your independent task and then resume when you're ready, good luck.

Super job, everyone.

So we know that A was true, B was false so we did not take that.

C was also true, team C did have two fewer units than team B.

D was also true, so we give that a tick.

Now for E, we should have known that the difference between team A and team E's volume is three units.

Well, if we know team A had filled up three units, that must mean three plus the difference, three plus three, is equal to six.

And the difference between team C and team E's volume is one unit.

Well, we know that team C was able to transfer five units.

So five plus one is also equal to six, which means that team E was able to transfer six units so their volume was six units.

Great job, everyone.

If you'd like to, you can share your work with Oak National by asking your parent or carer to share your work on Instagram, Facebook or Twitter, tagging @OakNational and #LearnwithOak.

As always, don't forget to complete your final quiz, and I really hope to see you next time, bye.