# Lesson video

In progress...

Hello everyone, it's Mr. Miller here.

In this lesson, we're going to be looking at the Indian number system.

So, first of all, I hope you're all doing well.

In the last couple of lessons, we've had a look at both our own number system, the base ten number system, as well as the base five number system, and we saw what was different with that.

Really exciting that, in this lesson, we're going to be looking at the Indian number system.

Now, this is actually the way that they count numbers and use numbers today in India.

So, if you ever were to go there, you would be able to talk about the same numbers that they use.

So, on this slide to try this task, I've put in the standard short scale system, which is our number system, as well as the Indian number system and I want you to have a think What's the same? And What's different between these two systems? Have a think for one or two minutes.

Pause the video now.

Okay great so, hope you saw that what's the same is that starting off with the ones, tens, hundreds thousands, up to ten-thousands that it is the same between both number systems. Both number systems count up to ten thousands exactly the same but then it gets a bit different because in our system we know that we have hundred thousands and then millions and then ten millions, etc.

But they call it something slightly different in the Indian system.

They call it lakhs.

I don't know if I'm pronouncing that correctly but lakhs, and then crores.

So, they have a different name for that system but also what's different as you might have noticed is the way that the numbers are written.

So, we know that in our number system we always group together the numbers in groups of three.

So you can see if we were writing a hundred million we've got three zeros here three zeros here and then three digits here always in groups of three.

But in the Indian number system that is slightly different, because the final group of three, they have these three digits, but then after that they always have it in groups of two so we can see that ten crores, we've got ten, zero zero, zero zero, and then finally three zeros.

So, although one hundred million and ten crores are the same value, there is a different way of saying it and writing down the number.

And it's this difference that we are going to look at in more detail in today's lesson.

So, let's get ready and have a look at the connect slide.

Okay, for the connect task, I'm showing you exactly the same table as we had before.

This time there are three numbers that we need to express in both the standard short scale system, and the Indian number system.

Now, we are going to go through each of these three together, before you have a go yourself in the independent task.

So let's have the first one.

First of all we can see that we've got the number written, in the standard short scale system.

How would we write that number in words? Well, should be quite straightforward, we know that this is fifty thousand so we can write that in.

Now, thinking about this in the Indian number system we know that this is called fifty thousand, and we also know that up until the ten thousands the two number systems are exactly the same.

So we write this in the same way as five, zero, zero, zero, zero.

So that's the first one done.

Nice and straight forward, they are exactly the same.

But it's when we get above the ten thousands that the two number systems change as we said before.

So let's have a look at the next one down.

First of all, nice and straightforward, how would we write that in the standard short scale system? Well, clearly this is three hundred thousand, so I'll just write that in.

It's three hundred thousand.

And the table said that we write this as three lakhs, but how would we write this in digits in the Indian number system? Well, we could use the table to help us, but the critical thing is thinking about how the Indian number system groups the digits.

And the key thing is, is that, the final three digits.

We have a look at the final three digits, that is in a group of three, so going backwards, that's the final group of three.

But then, from then on, we've got groups of two.

So I need to have a look at the next two digits which are both zeros and put them in their own group of two.

Like that I've got one more digit which is a three, and I write that by itself and there is my number three, zero zero, zero zero zero, which I can see if I look up to the table is three lakhs.

Okay, how about the final one, twenty five million? How would I write that in the standard short scale system? That's really nice and straightforward, because we are really familiar with this all ready.

Twenty five million is twenty five, followed by three zeros in a group, and then three zeros in a group.

And I can put in commas as well you might be used to doing that, that is absolutely fine.

The key thing is that the groups are separate Okay, how do we do this in the Indian number system? Feel free to pause the video if you feel confidant on how to do this.

We'll if you don't that's okay because this is, slightly tricky.

Let's go through it together.

As we did before, we are going to think about this in terms of groups of numbers.

So I start off with the final three zeros, which I can see are in a group together, and then I need to count in groups of two.

So I've got two zeros here, and then I've got a zero and a five, and then a final two by itself.

So I've got two, five zero, zero zero, zero zero zero.

How would I write this as an Indian number? Well have a look at the table to help you.

This digit here represents my crores, so I've got two crores, and then next, I've got fifty, so what does that fifty mean? Well that is fifty lakhs, and then that's it.

The next group is in thousands but I don't have any of them so I just leave it as two crores, fifty lakhs.

Okay, so the key thing here to remember, before you do this yourself, is that the Indian number system has different groupings.

The final three digits are in a group together, and then we've got groups of two going backwards.

Hope that's pretty clear, now it's your turn, let's have a look at each independent task.

Okay, so here's what you have to do.

The example says I have got two hundred thousand, four hundred and seven.

And I can see that it's written in the standard short scale system.

And I can write that out as two hundred thousand, four hundred and seven.

Also, in the Indian number system that is, two, zero zero, four zero seven.

Which is two lakh, four hundred and seven.

So, three numbers for you to have a go at.

First of all, you need to think are they written in the Indian system? Or the standard short scale system? And then, you need to convert them to the other system, and write them both in words in both systems. Hope that's clear, pause the video now.

Four or five minutes, have a go at these three different numbers.

Okay, great, answers are coming up now.

And just to go through these super quickly, the first one is written in the Indian system, as one lakh, thirty thousand, and we can convert that to one hundred and thirty thousand in the standard short scale system, The next one is in the standard system and we can write that as five million, two hundred thousand, and eighty, and then converting that is fifty two lakh, and eighty.

And the final one is fifteen million, which is one crore and fifty lakh.

Okay, well done if you had a good go at that, I know it's slightly tricky, but it's something to get used to, so well done if you had a good go.

Let's have a look now at the final slide now, the explore slide.

So again, it's a pretty similar thing, this time we have got four different statements.

I need to fill in the box, using a less than, a greater than, or an equals sign.

So what I want you to do is have a think about how you would write each of these in the same system, or converting them to the same system, to find out which one is bigger or not.

Let's do the first one together to set you up.

So I can write a hundred thousand as one hundred thousand, like that.

And then ten lakh will actually, I can go to my table and I can see that that is ten lakh all ready written for me which is, one zero, zero zero, zero zero zero.

And then what I could do here, is I could just count the number of zeros, and I can see that ten lakh has got more zeros, or I can convert this into the standard short scale system so I know that I've got a group of three to finish off with and then I need to have another group of three, zero zero zero, and one.

So this is actually equivalent to a million, in the standard short scale system.

So therefore, what do I put in the box? Well, a hundred thousand is less than one million, so that is the sign I need.

Okay, now it's your turn to do the final three, so pause the video, and have a go, see how many you can get right.

Okay great, let's go through these together.

So five lakh is going to be five, zero zero, zero zero zero which is actually exactly the same as five hundred thousand they have the same number of zeros, they are equal to each other.

The next one, well I can write six million, and forty thousand out, that is six million and forty thousand.

That's in the standard short scale system.

And this one to the left, I can re-write that in the standard short scale system, remembering that I need groups of three now, ending with two hundred there and then before that, zero four zero.

and a six So comparing both of these numbers which are now in the standard short scale system, I can see that the one on the left, is bigger than the one on the right by two hundred, So I need a greater than sign here.

The final one.

I can write twenty two million out, like that, nice and easy, two crore, two lakh, well lets go to my table, I know that two crore goes in here, and then two lakh, well that is going to be, zero two, and then I fill out the rest, so zero zero, zero zero zero.

So I've got crore here, lakh here, thousands here, and then hundreds there.

And then I can put this as two.

I can write this as twenty million, two hundred thousand.

So I can see that this first one is bigger.

Okay, so that is it for today's lesson.

We have had a look at a completely new number system, the Indian number system, so, hope that you found it interesting and enjoyable, and next time we are going to actually have a look at my favourite lesson in this unit, which is looking at the Mayan number system.

So hope you are looking forward to that.

Thanks for watching the video today.

Have a great day! and I will see you next time, Bye.