# Happy maths 1: numbers

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Happy Math 1: Numbers, by Mala Kumar

©Pratham Books, 2007 First Edition 2007Illustrations: Angie&Upesh ISBN 978-81-8263-906-5Registered Office: PRATHAM BOOKSNo.633/634, 4th “C” Main, 6th ‘B’ Cross, OMBR Layout, Banaswadi,Bangalore- 560043.&080 - 25429726 / 27 / 28 Regional Offices:Mumbai&022 - 65162526 New Delhi&011 - 65684113 Typsetting and Layout by: The Other Design StudioPublished by: Pratham Books (External Link) 

Sankhya and Ganith have been learning a lot of things in their mathematics class.Join Sankhya and Ganith in their happy discoveries about mathematics.Zzero and Eka are friends of Sankhya and Ganith. In this book Sankhya and Ganith discover the magic of numbers. They think of numbers as their friends.They want to share some of the things they have found out about numbers.They learnt about numbers from stories that they read in many books in their school library.

## The big challenge

Eka: Zzero ! Will you stop bouncing around like this, please?
Zzero: I’m happy. So I’m bouncing. I can take on so many shapes.

Eka: Stop boasting. Do you know how many numbers you can make up? 0, 10s, 100s, 1,000s and 10,000s. That’s a lot of numbers.0, 10, 20, 30, ….90, 100, 101, 110, 200, 201, 210, ….

Zzero: Please stop! I want to find out how many numbers exist between 0 and 10,000 with one or more zeroes in them. The firstone is 0 and the last is 10,000 so that makes two…

Eka: Zzero, hats off to you for saying you will take up such a BIG challenge. I think you should first try to find out how manynumbers have one or more zeroes between 0 and 1,000.

Readers, can you help us please ?

## Grains of rice

Acharya Vinoba Bhave was a freedom fighter. He followed the teachings of Mahatma Gandhi and lived between the years 1895and 1982.

When he was a young boy in Maharashtra, his mother had made a vow of offering 10,000 grains of rice to God. She carefully counteda hundred grains each day and offered it in prayer, reciting God’s name each time she made an offering.

Vinoba’s elder brother had an idea. He said, “Mother, why do you do this everyday? After counting a hundred grains on oneday, measure its weight. From the next day, you just have to weigh out an equal amount and offer it to God. This will save youtime and effort.”

Vinoba said, “I don’t think that would be right. When you count 100 grains of rice each day, you will repeat God’s name 100 times.But if you weigh out 100 grains, you would say God’s name only once!”

Vinoba’s mother wanted tooffer 10,000 grains of rice. If each grain weighs half agram, how many grams will 100 grains weigh?

50 grams. If one grain weighs half-a-gram, 2 grains will weigh 1gm. How many 2’s in 100? $\frac{100}{2}=50$ . $50\times 1=50$ .

If Vinoba’s mother had counted hundredgrains on Day 1, and then followed her elder son’s advice,how many times would she have said God’s name till she made the complete offering?

199 times. On Day 1, she would have uttered God’s name 100 times while offering hundred grains. That would leave 9900grains (10 thousand minus 100 = 9900). 9900 divided by $100=99$ . $100+99=199$ .

#### Questions & Answers

how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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