Merry Christmas and Happy New Year

All de best wishes...........

Olympiad Resources

http://www.kvntpcbadarpur.com/Olympiad.htm

http://www.ebook3000.com/International-Mathematical-Olympiads-1959-1977_10527.html

http://www.pdf-search-engine.com/math-olympiad-pdf.html

http://knowfree.net/2008/04/19/mathematical-olympiad-in-china-problems-and-solutions.kf

Nothing is limited here!

As we have many great members in our group, more and more books are available now! We are so delighted to inform all members that the following books are available for you now, just send us the name of the books, you'll get as soon as possible....

Romanian Mathematical Competition 2003
Romanian Mathematical Competition 2004
Romanian Mathematical Competition 2006

Let Solve this problem:)

3 men play a game with the understanding that the
loser is to double the money of the other two . After 3
games each lost just one and each has $24 . How much
each have at the start of the game ?

Some Tips for Singapore Scholarship

As requested, the following info may help you to prepare for SG scholarship, THE SECOND ROUND, after you pass khmer exam.

Although, the first round hasn't started yet, it is important that you prepare for the second round. The reasons are: 1. It is only a week (usually) after the application result release that you will take the 2nd round 2. Unlike first round, the 2nd round is the SG turn to set the problem for exam. It might be very difficult compare to our standard highschool level especailly, to the best of my knowledge, for Physic, Chemisty and Biology.

The process may be found here. (it is written by sister Sokly)
http://www.khemaracorner.com/blog.php?id=70

OK now here is the process i recommend.

1) Knowing / Deciding what subject/major you will study in SG.

-Although it might look easy. Indeed, it was the hardest part for me, because once you select yr major, your whole life/ study here will be like that. Can't change. So make sure you study what you like. Right now i'm glad to study my be loved subject, Computer Science. :). This link contain all the subject that you might be able to apply.

http://www.nus.sg/oam/course/

Pls also be noted that, not all subject you can study. For example, Aero Space Engineering is the toughest subject here. They might not allow you to take it. For BIO/MEDICAL i am not sure, but the probability that you pass is low also.

2) Prepare for Entrance exam base on the major you choose.

-i) Normally in filling the application form, you will have to select three/five choice.

-ii) Because last year, NTU was the host to exam, I am 95% confident in saying that, this year, the exam will be in NUS format. Dun worry, some of you may not understand what it mean. It doesn't matter. NUS format has Part A B C and NTU is not like that. You will know when you download the exam syllabus.

-iii) Please visit this site to understand more as well as knowing which subjects you will have to take in 2nd round :

http://admissions.ntu.edu.sg/undergraduate/singapore/admission/Pages/CategoryE.aspx

For example, if you choose to study economic there you will have to take {Math AO, Humanity, English }. If you choose computer engineering you will have to take { Math A, Physic A, English}.

3) How to prepare syllabus after you choose major you like and knowing which subjects you are going to deal with in exam:

http://www.nus.edu.sg/oam/apply/catd/uee/paper.htm

This link contain all the syllabus and sample. (It is at the bottom of the page/webpage)

4) Preparing Document:

Unfortunately I only know abt MATH A level/ MATH AO LEVEL/ PHYSIC/ English.

i) FOR math both AO and A level it is a huge benefit and enough if you study throught this wesite:

http://www.wtamu.edu/academic/anns/mps/math/mathlab/col_algebra/index.htm

This web has sufficient knowledge to pass you the entrance exam. Remember to study within the syllabus area.

I don't know that website when i were preparing and i just know it now. Consider you r lucky.

For MATH AO level, there are some books at Hunsen Library. Find a book(s) with title Math AO level (=Ordinary level)

iii) English, it is not as hard as physic but at least it is still hard. Writing skill /reading/ vocab can learn from Toefl. If you are strong enough you can try SAT.

this website might help also :

http://admissions.ntu.edu.sg/undergraduate/singapore/admission/Pages/CategoryE.aspx

Beside that pls visit this link to see how excited you are if you pass :

http://gallery.ntu.edu.sg/photos/v/facilities/

(MY school view)

That's all i can help. Hope you pass.

Finally i would say girls are welcome than boys. haha you will understand when you come to live here. Only two girls are with us right now.

Cheer

Check it out!

More books and documents are available now, please have a look if you are interested in or not!

1. Math Wonders to Inspire
2. 102 Combinatorial Problems
3. Complex Numbers from A to Z
4. Putnam and Beyond
5. The USSR Olympiad Problem Book
6. Geometric Problems on Maxima and Minima
7. Erdos-Mordell inequality TA
8. Contests Around the World 1999-2000
9. Contests Around the World 2000-2001
10. KedlayaInequalities
11. Olympiad Inequalities 2006 ( by Thomas J.Mildorf )
12. cartetitu Problems

PS: I wanna give a big thanks to Thya, a member from sisowath high school, who sent us her personal documents and books to share with all the members.

Moreover, we would be delighted if all members are active in our group discussion.

Requested Books

Haha hello guys!

 i know i am so passive these day. haha until muy geuch email to ask me teat.:)) thanks muy geuch...

Sorry I've just finish my exam. Hmm what am i supposed to do now.....

Well let first deal with the requested books: 

Here are the upload files i uploaded. you guys can download free:

But notice that some files are in DJVU. DJVU is a program that must be used to view those files. If you haven't had it you can download as i upload here already. Try to use the program first. If you don't know how to use DJVU to view file you can post commet for help. Anyway it is totally easy to use DJVU. 

    DJVU viewer

1. Challenging Problem in Algebra

3. Mathematical Olympiad Tressure
4. Mathematical Olympiad Challenge
5. 102 combimonatoric problems

for User Olympiad book i will search and upload if i find.

By the way for those who email me to get IMO english version. I think you guys don't know abt      IMO compendium.pdf yet? if so i would recommend you to pratice this book.

You can either ask The web master__ Reasmey for a copy or downlaod by simply click here.

Cu

Jupiter 

Books we are finding!

Hello everyone! As the group is having some problems in finding some books in software, we would like to ask everyone if you have any of these books as following:

1. Challenging problems in Algebra
2. The user Olympiad problem book
3. Mathematical Olympiad Tressure
4. Mathematical Olympiad Challenge
5. 102 combimonatoric problems

We will be so delighted if you can share with us, just send to the group mail group_cmg@yahoo.com ! Your participation will contribute alot to Cambodian future in Math competition! Thanks in advance....

Anyway, I would like give a big thanks to Sakheyna, a member from Sisowath, who us his books including Math contest around the world 1999-2000 and Math contest around the world 2000-2001. So everyone can have these books.... Thanks again

Further added members!

Since we have many membership application forms remaining, we finally decided to select more members! Please see the following list:

Chan Marisa
Chim Eangchhe
Chhay Taklida
Chheng Phiron
Heng Piseth
Hong Makara
Hong Sothun
Keam Kongleaphy
Kheng Sovansak
Kien Forcefidele
Koch Sivkong
Meng Phanny
Nak Sreyleap
Nguy Kealong
Norn Saophanith
Prum Seiha
Sea Lihoung
Teik Solida
Uk Samphal
Ung Sunmeng
Veung Vouchlin
Veung Vouchly
Yem Marady
Yem Veasna

Singapore scholarship is available now!

As every year, Singapore scholarship is the first released amongst other Bachelor degree scholarship, following by China, Japan, Malaysia and some others. This scholarship is usually offered to 2 to 3 Cambodian outstanding students ( who pass all the stages ) to study with full scholarship ( 100% free and even get salary from about 400$-800$ depending on your performance and year of study) in Bachelor degree in Singapore, a great education country. Students who are interested in this, please go to buy the Khmer form at Scholarship office ( just near Apsara TV station ). There will be a form shorted list test, a few exams and interview for those who pass the previous stage.

The first selection test will be on 31 December 2008.

Geometry problems of the week!

Dear all members, please try to solve these exercises, we will be able to improve your geometry skill! Try to think it one by one, consider it carefully... You may be able to discuss these problems at www.groups.google.com/group/groupcmg .... Enjoy!

1.(Chinese Mathematical Olympiad, 2007) Triangle ABC is not isosceles. The incenter is I, the excenter is O. The incircle touches the sides BC, CA, AB at points D, E, F, respectively. Lines FD and AC intersect at P, lines DE and AB intersect at Q. The midpoints of segments EP amd FQ are M and N, respectively. Prove that MN and OI are perpendicular.

2. Determine the locus of the centres of all regular triangles circumscribed about a given acute triangle. (The triangle G is said to be circumscribed about the triangle H if the vertices of H lie on the sides of G.)

3. Given a convex quadrilateral ABCD and a point P in its interior such that AP=CP, and. Prove that DA.AB.BP=BC.CD.DP.

4. The angle bisector drawn from vertex C of an acute angled triangle ABC intersects the opposite side at the point F. The feet of the perpendiculars drawn from the point F to the sides BC and CA are P and Q, respectively. Let M denote the intersection of the lines AP and BQ. Prove that AB and CM are perpendicular to each other.

5. A' is the reflection of the vertex A of an equilateral triangle ABC about the opposite side. A line passing through A' intersects the lines AB and AC at the points C' and B', respectively. What is the locus of the intersection of lines BB' and CC'?

6. The angle bisectors of triangle ABC intersect sides BC, CA and AB at points A1, B1 and C1, respectively. On line A1B1, denote by F the perpendicular foot point of C1. Prove that line FC1 bisects angle AFB.

7. Let h denote the length of the tangents drawn to a circle from an exterior point P, and let the midpoint of the line segment connecting the points of contact be F. Prove that a chord AB of the circle satisfies the equality AP.PB=h2 if and only if the line AB passes through the point P or the point F.

8. The angle bisector drawn from vertex C of an acute angled triangle ABC intersects the opposite side at the point F. The feet of the perpendiculars drawn from the point F to the sides BC and CA are P and Q, respectively. Let M denote the intersection of the lines AP and BQ. Prove that AB and CM are perpendicular to each other.

Starting the Blog

To all my respected senior members && friends who are willing to contribute to blog,

As having been viewing and posting some comments or post here together, I hope you all are commited to improve the math development in Cambodia together AS MUCH AS we can despite how busy we are. I do understand you are busy, that why I said AS MUCH AS possible. I am too busy with my university also, but I always spend some of the time i could to do sth useful for this blog such as posting, or sending some soft_copy of math book to dararasmey to share the member. I hope you all will think the way I do too, and i can see some of the senior like bong Sovanvichet even giving the book he wrote himself free. Thanks so much.

Now, the time won't wait. Yesterday is a history, tomorrow is a mystery , but today is a gift. (Uqoi :)). So, let begin the first step of developing blog by simply planing what we will/ should do.

1)should it be a good idea to have problems solving challenging?

To encourage the incentive of solving the problems, I would suggest a policy of giving credit to all members who solve problem we post here ORIGINALLY (not copy from book). Giving credit mean that, whenever a member solve a problem we will get one credit or score added to the database of the respective member. By the end of each month/year/ or even more competitive , week. We would do sth that please the first three top persons with the highest credit. Unfornately, there is no online judge like programming, so i guess, some of our senior (can also be me) would be the judges for weekly posted problem.

2)Database system

 Any IT senior member who already study&& can write database? can Bong help me to write one to do the following job: store all member INFO?, add new member info, remove members, and other common task. I would say I can too, but I only use java and i'm just start Object Oriented Programming this semester, so not yet fluent. I would appreciate if any one can help me. 

3) Category && Disivions

 Moreover, it might be the time to think now how to divide the blog into subsection of grade. This might help the lower grade students/member to perform better. We can also divide post into, small topics, such as arithmetic, geometry, inequality, number theory, combinatorial problems and sth else.

That all the initial Ideas i could think of tonight.

SO what do all my friends and my respected senoir think? any more good idea or comments?

Bong, sovanvichet...., Bong dararith,...and Other senoir.... please together we find a good ways to promote mathematics velocity in this blog, as well as in cambodia, as it is all our goal despite of our busy time.

Thanks,

Younger,_senior member,

Pheng Sovanlandy

Recent added members!

There are totally 43 recent added member which include: grade 9 ( 2 members ), grade 10 ( 12 members ), grade 11 ( 19 members ), grade 12 ( 4 members ), year 1 ( 3 members ), year 2 ( 2 members ) and year 5 ( 1 member).

If you see your name as following meaning that you are now becoming our group member! Please comfirm your email since there were some errors with some your emails which we could not reach.

Chan Sopheaktra
Chea Laline
Chea Pumsakheyna
Chet Stravy
Chhun Vannkuthea
Chov Prelsor
Eang Utdomvattanak
Eap Vithyea
Hen Pisithkun
Heng Samnang
Hong Panha
Hout Samnang
Hun Dararithy
Huy Chandara
Khun Pisith
Leng Sivlyza
Lim Ouy
Lim Sobunnavath
Lov Kimtheng
Men Chanpheaktra
Mong Sorikrath
Mony Sorithisey
Nak Bunna
Nong Yonsothya
Norn Sereyrith
Ouch Kithya
Pen Nakry
Pen Vuthy
Phav Makara
Phon Pechchenda
Sam Sokpanya
Sarim Bonita
Seng Hour
Seng Kruy
Seng SovanMinea
So Sakakrona
Taing Uytry
Tang Monyreach
Tek Hangnita
Teng Vannara
Uk Chamnan
Vichet Pisey
Yan Kunthea

Being our member, you can have those available books in our group and further suggested books ( if possible ) by just leaving us comments or send us directly to our mail.

Korean Scholarship is available now!

This is a full scholarship for Cambodian students who have good personality and proper ability ( as requirement ) to study Bachelor degree in the major of Marinetime for 3 years in Korea Marinetime University in Busan, Korea. This scholarship is offered by SOMA group; 3 competent students will be selected.

Requirement :

_High School Diploma ( finished grade 12 )

_IELTS 5.5 ( minimum ) or equivalence

Deadline : 8 November 2008

Please contact us for more detail.

Please see this website : http://english.hhu.ac.kr/english/

Attention to all new members!

If you are now selected to be our group new member, you will have a great chance to get many cool Mathematics books in software ( PDF or DJVU )! Please email us if you want to get any of the following books:

Elementary Level( 9th grade or below ):

Elementary Math Word Problems ( 2005 )
Introduction to Proofs ( unofficially prepared by CMG member in 2007 )

Intermediate Level ( 10th-11th grade ):

Junior Balkan Mathematical Olympiad ( 2003 )
Topics in Inequalities ( 2007 )

Olympiad Level ( 12th grade ):

Chinese Old Book ( Not sure for the Year! Written in Chinese )

Challenging Problems in Geometry ( 1996 )

Olympiad Problems from Arounf the World ( 1997 )

Problem-solving strategies ( 1998 )

Mathematical Problems and Proofs ( 2002 )

Math Olympiad Problems Collection ( 2003 )

103 Trigonometry Problems ( 2005 )

The IMO Compendium ( 2006 )

104 Number Theory Problems ( 2007 )

Mathematical Olympiad in China ( 2007 written in English )

Romanian Mathematical Olympiad ( 2007 )

New World Selection I ( Unofficially prepared by CMG member in 2007 )
New World Selection II ( Unofficially prepared by CMG member in 2008 )

University Level:
The William Lowell Putnam Mathematical Competition 1985–2000 ( 2002 )
Advanced Calculus with Application in Statistics ( 2003 )
Mathematics for Computer Science ( 2004 )
Hypercomplex Numbers in Geometry and Physics ( 2004 )

Unsolved series:
Solved and Unsolved Problems in Number Theory and Geometry 1 ( 2000 )
solved and Unsolved Problems in Number Theory and Geometry 2 ( 2000 )

Must Read it!

Programming Contest

For those who like doing math AND programming, GOOGLE this: ACM ICPC programming contest!

CoDe YoUr BrAiN!!!

http://cm2prod.baylor.edu/login.jsf

Rule of Inference, out of date Joke. haha

Do you know therefore lim(x-->5)(1/(x-5))= what?

Math is actually fun!

Knowledge=Power (1)
Work=Power.Time , Thus Power=Work/Time (2)
But Time=Money (3)
(2) & (3) , We get Power=Work/Money (4)
Replace (4) in (1) , we get:
Knowledge=Work/Money , Thus Money=Work/Knowledge

Therefore, when Knowledge approaches to infinity, the Money approaches to 0
And When Knowledge approaches to 0, the Money approaches to
So, if you do NOT understand any of this you will SOON be RICH, ha ha!

Additional && Advance Problem on pigeon Hole principle, (By Jupiter)

Pigeon hole principle is quite easy to understand. Now look in this pictures. Suppose 10 pigeons are about to fly into 9 holes. Then there must be at least one hole that contain more than 1 pigeon. As a real example you can see here.

U may understand, it is impossible to have all the holes contain no more than 1 pigeon! (unless pigeon fly fly then disappear haha).


The problems here are all have solution. But i will post them in 2 week more time. I reason is, i want you guys to try to solve it together and get to know and learn from each other. For those who can solve please be sure to post yr solution in 2 week time. I would appreciate that. It require somehow my effort to post and write solution, So would you appreciate my effort by simply try to solve the problem and post yr good solution? I'm sure all mathematician like other to admire their solution including me.:D

As Smey has stated, The pigeon Hole principle is simple. Yet it application is so useful. He also posted some quite useful theorem, so you should take note it...

In my opinion, pigeon hole principle should be called dirichlet principle. Dirichlet was the one we owed for that theorem. There are two important theorem you should take note:

Theorem 1 : If k+1 or more objects are placed into the k boxes, the there is at least one box containing two or more of the objects.

Theorem 2: Generalizing: Let there be k1 boxes. If N or more objects are placed into the k boxes, then there is at least one box contaiing at least [N/k]+1 objects, where [a] denote the floor ceiling function of integer a. [4.5]=4 [-3.1]=-4.

As i have commited, this blog is for all level. I won't post problems that too hard nor too easy. Enjoy yr level!

Beginner Level:

1) A drawer contains 10 black socks and 10 white socks. You reach in and pull some out without looking at them. What is the least number of socks you must pull out to be sure to get 4 of the same color?

2) Show that in a group of 85 people at least 4 must have the same first initial of their names.

3) A bowl contains eight red balls, ten green balls and nine blue balls. A student selects balls at random without looking at them.
(a) What is the minimum number of balls the student must select to be sure of having at least two balls of the same color?
(b) What is the min number of balls the student must select to be sure of having at least three balls of the same color?
(c) What is the min number of balls the student must select to be sure of having at least three GREEN balls?


Intermediate level:

1) Let ABCD be a rectangle with AB=8, BC=9. Show that if select seven points in the interior of the rectangle, there are at lest two whose distance apart is less than or equal to 5.

2) There are 5 distinct points with integer coordinates in the {x,y} plane. Show that there must exist at least one pair of these points such that the midpoint of the line joining these two points also has integer coordinates.

3) Let S={2,5,8,11,14,...,71,74,77,80}. How many elements need to be selected from S to ensure that there will be at least two whose sum is 82.

Slightly Advance Level

1) Bill sent out at least one SMS message each minute during a period of exactly one hour. He sent a total of 70 messages over this duration. All these messages were sent to 16 friends and some of them received more than one message from him. Prove that there was a duration of a number of (consecutive) minute which bill sent out exactly 49 SMS messages.

2)Let S be a set of eight positive integers each of which is less than 30. Show that there must be two distinct subsets of S whose elements add up to the same sum. For instance, if the eight numbers are {2,4,5,8,12,15,18,24} , the two distinct subsets can be {2,4,12,15} and {4 , 5, 24}. The sum of both of these is 33.

3) Prove that in any permutation of the twenty_four members 1, 2, 3,..., 24 there must be at least an occurrence of four consecutive positions in the permutation containing numbers that are less than 20.

4) In a box there is a deck of personal identity cards. Each card contains a birthday information (d,m,y) where d, m, y are integer numbers referring to date, month and year respectively. Suppose you reach in the box and draw some cards without looking at them. What is the least number of cards you must draw so as to get two cards, whose birthdays (d1,m1,y1) and (d2,m2,y2) have an even sum. i.e (d1+m1+y1)+(d2+m2+y2) is even?

5) Jack picks 25 integers from 51, 52, 53, ... 97 and 98. Prove that among the 25 integers are three integers whose digits sum up to the same amount. Fore example, the sum of the digits of integer 52 is 7, which is the same as that of the integers 61, and 70.

Advance Level!

1) Given 27 distinct integers, prove that there must be 2 integers whose sum or difference is divisible by 50.

2) Prove that there exist integer x>3 such that 3^x has remainder 1 when divide by 10^10.

3) Given any 5 distinct real number a1, a2, a3,a4,a5. Prove that regardless of how the 5 number are chosen, we can always find two index i, j of number such that a[i]-a[j] is between in gap ]0, 1+a[i]a[j] [

Magic Math book is to be released in these few days!

Magic Math book, which is the first publication of the group, is to be released during Read Exhibition at Alliance Fance du Cambodge from 23-25 October. However, since we have a little problem with the publication, the book may be able to be sold from the 2nd and 3rd day of the exhibition which from 24th October evening, thus please wait for a moment for purchasing this book.

The purposes of the publication of this book are:

to share all my knowledge regarding the way of solving mathematical problems espcially for national and international outstanding student competitions and scholarship exams

to encourage all Cambodian Generations to focus on Mathematics

to contribute strengthening human resources in Cambodia

to help students who love mathematics to be able to understand easily.

Hope all of you will support this publication.

Along with this book, I've created this blog for sharing competition experiences, solving mathematics strategies and mathematics documents.

Complete this form now to be our member!

Suggested problems to be solved! Let's try together

By using Pigeonhole Principle Prove that:
1-There exist two powers of 3 whose difference is divisible by 1997.
2-There exists a power of three that ends with 001.

Be patient !!

Actually, the blog now just like a baby who havent come out of mother's body.. You know, his mother have not even born so how can the baby come out??? Be patient !! Magic Math book will be released soon on Friday 24th October 2008 and it will be first available in READ EXHIBITON which will be held in Aliance ( France School). Moreover, after it's alive, we still need time to adapt it step by step so just be patient!!

Hopefully, all math genius here will enjoy contributing this blog!!

Our blog are alive now!

The Pigeon Hole Principle (a part of Introduction to proof book)

The so called pigeon hole principle is nothing more than the obvious remark: if you have fewer pigeon holes than pigeons and you put every pigeon in a pigeon hole, then there must result at least one pigeon hole with more than one pigeon. It is surprising how useful this can be as a proof strategy.
Example
Theorem. Among any N positive integers, there exist 2 whose difference is divisible by n-1.
Proof. Let a1, a2, ..., an be the numbers. For each ai, let ri be the remainder that results from dividing ai by n - 1. (So ri ai mod(n-1) and ri can take on only the values 0, 1, ..., n-2.) There are n-1 possible values for each ri, but there are n ri's. Thus, by the pigeon hole principle, there must be two of the ri's that are the same, rj = rk for some pair j and k But then, the corresponding ai's have the same remainder when divided by n-1, and so their difference aj - ak is evenly divisible by n-1.
Example
Theorem. For any n positive integers, the sum of some of these integers (perhaps one of the numbers itself) is divisible by n.
Proof. Consider the n numbers b1 (a1) mod(n), b2 (a1 + a2) mod(n), b3 (a1+a2+a3) mod(n), ..., bn = (a1 + ... + an) mod(n). If one of these numbers is zero, then we are done. Otherwise, only the n-1 numbers 1, 2, ..., n-1 are represented in this list, and so two of them must be the same, bi = bj (say i < j). This would then imply that (ai+1 + ... + aj) mod(n) = 0, proving our claim.
Exercises
Prove each of the following using the pigeon hole principle.
If a city has 10,000 different telephone lines numbered by 4-digit numbers and more than half of the telephone lines are in the downtown, then there are two telephone numbers in the downtown whose sum is again the number of a downtown telephone line.
If there are 6 people at a party, then either 3 of them knew each other before the party or 3 of them were complete strangers before the party.

Relax! back at one

Books available in software!

Introduction to Proofs
New World Selection I
New World Selection II

Elementary Math word Problems (7th Grade)

12th grade—International Books
Advanced Calculus with Applications in Statistics
103 Trigonometry problems
104 Number Theory Problems
The William Lowell Putnam Mathematical Competition 1985-2000
Hypercomplex Numbers in Geometry and Physics
IMO Competition 1959-2004
Mathematical Problems and Proofs, Kluwer Academic
Math Olympiad problems Collection, version 1
Math Olympiad Problems and Solutions from around the world 1995-1996
Topics in Inequalities - Theorems and Techniques (1st Edition), Hojoo Lee
Mathscope, Vietnamese journal
Math Excalibur
IMO Compedium

Good tips for Mathematics Olympiad participants!

The term "olympiad" is used generically to refer to a math contest in which students are asked not to compute numerical answers, but to give proofs of specified statements. (Example: "Prove that 2003 is not the sum of two squares of integers.") The most famous example is the International Mathematical Olympiad; most countries that participate at the IMO have national olympiads as part of their team selection process. Some areas have additional olympiads at the regional or local level.

The jump from short answers to olympiads is a tough one. Here are some tips for students making this transition.

Practice, practice, practice.

The only way to learn math is by doing.Proofs are essays. The better written a proof is, the more likely it is to be understood. Even such mundane things as grammar, spelling and handwriting are worth a bit of attention.

Define your terms. If you're going to use a word in a way that might not be commonly understood, define it precisely. Then stick to your definition!

Read the masters. No one ever learned how to do good mathematics in a vacuum. When you do practice problems, read the solutions even of the problems you solved.

There's more than one road. Different solutions can be equally valid; even when solutions agree in substance, differences in perspective can be significant and valuable.

It's not over when it's over. Don't hesitate to continue thinking about the problems on a contest after the time ends, or to discuss the problems with others.

Learn from your peers. They're smarter than you might have expected.

Learn from the past. Try to relate new problems to old ones; you may learn something from the similarities, or from the differences.

Patience. No one said this was easy!

let solve this classic theorem together...

OK so this is the first set problem for IMO 2009 students as well as for all young mathematicain. lolz.

1)Suppose there are seven coins, all with the same weight, and a counterfeit coin (fraud coin) that weights less than the others. How many weighings are necessary using a balance scale to determine which of the eight coins is the counter feit one? Give an algorithm for finding this counter feit coin.

Hint: the ans is only 2. lol

2) solve the same problem in case there are 11 coins and 1 counterfeit coin which is havier than others. (if possible try to solve the problem in case n coing and 1 lighter counterfeit coin)

OK here is the last one:

3) Each inhabitant of a remote village always tells the truth or always lies. A villager will only give a "yes" and "no" response to a question a tourist asks. Suppose you are a tourist visiting this area and come to a fork in the road. One branch leads to the ruins you wan to visit; the other branch leads deep into the jungle. A villager is standing at the fork in the  road. What the only ONE question you can ask the villager to determind which branch to take?

Hint: use logic lol, 

OH by the way smey, I have invented some java program that do some benefit job for math such as 

1 ) test whether a 9*9 table of an interger is a soduku or not. 

2) factorial a positive numbe for example : 60= [2^2].[3^1].[5^1]

dunno what else. lol just hope i can post on this website to reduce the time for calculation of math students. when i was in highschool if i want to factorial big number or test whether a number is prime or not it take so long. but now it take less than 1second lol.

Regard,

Old generation

Ah finally there is such a blog. Thaks to dara_rasmey for creating this one. cool!

OK i am willing to contribute to this blog as well.

Cheer!

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Books available are:
Introduction to Proofs : includes many types of proof
New World Selection I : Collection of International Olympiad problems
New World Selection II : Collection of International Olympiad problems+Soduku solving skills
New World Selection III : IMO compendium+Collection of International Olympiad problems
Precious Inequality : Collection of Inequalities problems
The Training of Cambodian IMO team 2008 : The meterials from Cambodian IMO team 2008

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