Cheenta. passion for mathematics.


Pause for a moment. Here is a food for thought:


What if you wanted to draw a square whose area equals the circumference of a unit circle? The side length of such a square has an incredible expression.

$$ \displaystyle{\int_{-\infty}^{+\infty} e^{\frac{-x^2}{2}} } dx $$

What deep mathematics is hidden in this beautiful relation?

What is Cheenta?

Cheenta delivers outstanding programs in Mathematics for Olympiads, I.S.I. & C.M.I. Entrance and College.

Since 2010, we have worked with hundreds of students from India, United States, UK, Australia, Singapore and Middle East

All of our classes are delivered exclusively live and online. Our main center in Calcutta (India) office hosts a reading facility for advanced learners.

Who are Teaching?

We have ex-Olympians and outstanding researchers who teach out of love for the subject.

In India: Indian Statistical Institute, Chennai Mathematical Institute, IISER, TIFR, Calcutta University, IIT KGP

Outside India: the University of Wisconsin Milwaukee (USA), University of North Carolina (USA), St. Louis University (USA), IMPA (Brazil), E’Cole (France)

Admission and eligibility

Admission to a Cheenta program is highly selective. The prospective student must first go through a trial class.

Our courses are significantly more intense than regular school or college programs. Apply only if you are thrilled by the beauty of mathematics.

Math Olympiad, I.S.I. Entrance and College Mathematics candidates form the core student body of Cheenta.

I.S.I Entrance Solution – locus of a moving point

This is an I.S.I. Entrance Solution Problem: P is a variable point on a circle C and Q is a fixed point on the outside of C. R is a point in PQ dividing it in the ratio p:q, where p> 0 and q > 0 are fixed. Then the locus of R is (A) a circle; (B) an ellipse; (C) a...

Why is it interesting to laminate a genus-2 surface?

Take a two holed torus. Draw some geodesics (simple, closed). You have found a lamination! But there is something deep going on, in the veil of this apparantly innocent exercise. Find out more.

RMO 2018 Problems, Solutions

This post contains RMO 2018 solutions, problems, and discussions. Let \(ABC\) be a triangle with integer sides in which \(AB < AC\). Let the tangent to the circumcircle of triangle \(ABC\) at \(A\) intersect the line \(BC\) at \(D\). Suppose \(AD\) is also an integer....

Interior Segment is small – RMO 2009 Geometry

A convex polygon \( \Gamma \) is such that the distance between any two vertices of \( \Gamma \) does not exceed 1. Prove that the distance between any two points on the boundary of \( \Gamma \) does not exceed 1. If X and Y are two distinct points inside \( \Gamma...

ফ্রি গ্রুপের গ্রোমোভ সীমান্তে একলা থাকেন ক্যান্টর

মানচিত্র আঁকছিলাম। রাস্তা গুলো সোজা সোজা। উত্তর, দক্ষিণ, পুব, পশ্চিমে যাওয়া যায়। এক ধাপ ডাইনে গেলে, সঙ্গে সঙ্গে এক ধাপ বাঁয়ে ফেরার নিয়ম নেই। (তাহলে আর ডাইনে গেলাম কেন!) তেমনি একধাপ উত্তরে গেলে, সঙ্গে সঙ্গে একধাপ দক্ষিণে ফেরাও মানা।

মানচিত্র আঁকতে আঁকতে দেখলাম এক উদ্ভট দেশ তৈরি হচ্ছে। সে দেশের প্রতি চৌমাথায় অসীম সব রাস্তা। সে সব রাস্তা আবার একে অপরের সঙ্গে তেমন দেখা সাক্ষাৎ করে না। এ হেন দেশের সীমান্ত নিয়ে আমাদের যত মাথা ব্যাথা। খুঁজতে খুঁজতে বেড়িয়ে পড়ল এক আজব কিস্যা!

সীমান্তে একলা দাঁড়িয়ে আছেন ক্যান্টর।

বাকি আড্ডা ভিডিও তে।

Sine Rule and Incenter – RMO 2009 Geometry

The Problem! Let ABC be a triangle in which AB = AC and let I be its in-centre. Suppose BC = AB + AI. Find ∠BAC. For any triangle ABC, \( \frac{\sin A}{a} = \frac{\sin B } {b} = \frac {\sin C }{c} \). Addendo: If \( \frac{a}{b}...

Cheenta and Singapore Method – creating Mathematicians of the future

Recently, French mathematician Cedric Villani’s team came up with ’21 measures for the teaching of Mathematics’. I read through the report, with great curiosity. I happily noted that Cheenta’s Thousand Flowers program has already implemented some of his recommendations.

Pythagoras Extended! – RMO 2008 Problem 6

Pythagoras theorem can be extended! What happens if the triangle is obtuse-angled (instead of right-angled?) We explore the idea by using a problem from Math Olympiad.

A rejoinder to the ‘Discovery’

Nehru writes, 'very little original work on mathematics was done in India after the twelfth century till we reach the modern age. 'Discovery of India' was written over five months when Nehru was imprisoned in the Ahmednagar Fort. It was first published in 1946....

RMO 2008 Solution of Problem 1 Cyclic Pentagon

Problem Let ABC be an acute-angled triangle, let D, F be the mid-points of BC, AB respectively. Let the perpendicular from F to AC and the perpendicular at B to BC meet in N. Prove that ND is equal to circum-radius of ABC. The discussion uses the following Theorems:...

Math Olympiad

An advanced program in Mathematics for brilliant school students. Taught by ex-Olympians and active researchers in Mathematics.

By the way, are you interested in the fourth dimension? Here is a beauty to behold! Tetracube created the beautiful image of the Omnitruncated tesseract.

Training brilliant minds.

Since 2010.

Cheenta has worked with brilliant maths and science olympiad students from over 6 countries. Our courses are specifically geared toward students with an exceptional interest in Mathematical Sciences.

Math Olympiad

Outstanding mathematics program for deserving school students.

Pre-Olympiad Thousand Flowers

For children who are starting out in Mathematics and Science.

I.S.I. & C.M.I. Entrance

For B.Stat and B.Math entrance at Indian Statistical Institute, B.Sc. Math at C.M.I. & KVPY.

College Mathematics

For I.S.I. M.Math, Mathematics Subject GRE, TIFR; Groups Analysis, Topology and more

I.S.I. & C.M.I. Entrance

B.Stat, B.Math Entrance at I.S.I. and B.Sc. Math Entrance at C.M.I. require special training in Number Theory, Geometry, Combinatorics and Algebra (apart from regular High School topics).

Problems from standard topics such as Calculus, Trigonometry or Coordinate geometry can significantly tricky.

Advanced Topics

Number Theory, Combinatorics, Algebra, and Geometry at Olympiad standard are both necessary and useful components of this course.

Regular High School Topics

Advance problems from Calculus, Trigonometry, Coordinate Geometry and Algebra are bread and butter for handling more complicated ones.

Not a spectator sport.

Think about the interesting problem!

College Mathematics

An advanced program for College Students as well as adults interested in modern mathematics. This program is useful for I.S.I. M.Math Entrance, Subject GRE, IIT JAM and similar entrances.

We work on Groups, Rings, Fields, Linear Algebra, Analysis, Topology and other advanced topics. As usual problem solving remains the driving force of the program.

The hyperbolic 3 space may come up in this course. Behold this beautiful Hyperideal Honeycomb created by Royce3 (under creative commons).

Continuing Education

Many adults, who are pursuing jobs or industry, have taken this program. A curious mind, coupled with a determination to take up challenges is sufficient.

Advanced GRE, TIFR, M.Math

This program is for the true math fanatic, who yearn to understand the anatomy of ‘reason’ a little better. Advanced problem-solving session every week!

What is Torsion?

Geometry is everywhere. Enjoy this bit.


“a wide range of mathematical topics, and every lesson is packed with insights and methods. We are extremely pleased with the difference he has been making. Under his tutelage Sam has secured several gold awards from the UK Mathematics Trust (UKMT)and Scottish Mathematical Council (SMC).” Jayanta Majumdar

Glasgow, UK

“Shuborno has been studying under Ashani from last one year. During this period, we have seen our son grow both intellectually and emotionally. His concepts and approach towards solving a problem has become more mature now. Not that he can solve each and every problem but he loves to think on the tough concepts. For this, all credit goes to Ashani, who is never in a hurry to solve a problem quickly. Rather he tries to slowly build the foundation..” Shubrangshu Das

Bangalore, India

“Our experience with Cheenta has been excellent. Even though my son started in Middle School, they understood his Math level and took personal interest in developing a long-term plan considering his strengths and weakness areas. Through out the semester courses they have nourished him with challenging problems and necessary homework. His guidance has helped my son to perform well at competitions including USAJMO and others. He has grown more confident in his math abilities over the past year and half and is hoping to do well in the future.

I am impressed with their quality and professionalism. We are very thankful to Cheenta and hope to benefit from them in the coming years. I would strongly recommend them to any student who wants to learn Math by doing challenging problems, specially if they are looking for Math than what their school can offer.” Murali Kadaveru

Virginia, USA