Mathraining

Mathraining is a training site for international math olympiads created by former Belgian IMO participants Nicolas Radu and Benoît Legat. It was created to be an interactive version of the training sessions in Wépion, which is used to train French Belgian students for international olympiads such as the BxMO, EGMO, and IMO. The language of the website is French, and it is free to use.

Users can gain points by training, and the website offers:

Theory

The theory section of Mathraining is divided into 6 sections, namely combinatorics, geometry, number theory, algebra, functional equations, and inequalities. Each section offers an introduction to the theory, and chapters, usually written by Nicolas Radu, which contains theory on the given topic. Chapters are divided into three sections:

• Les essentiels, which is basic theory essential for most Olympiads. This includes topics such as the Pigeonhole principle, cyclic quadrilaterals, divisibility and prime numbers, complex numbers, and AM-GM.
• Les classiques, which is more complex theory used in most international Olympiads. This includes topics such as graph theory, transformations of the plane, Euler-Fermat, polynomials, Cauchy's equation, and Jensen's inequality.
• Les pointus, which is advanced theory not used very often in most Olympiads. This includes topics such as double counting, cross-ratios, arithmetic functions, discrete calculus, and Hölder's inequality.

At the end of each chapter there are exercises on the theory. The solutions to these exercises are either numbers, or multiple choice answers. Solving these exercises gives 3, 6, 9, or 12 points based on their difficulty. There are currently 49 chapters and 266 exercises.

Problems

Just like the theory section, the problems are also divided into 6 sections, and can be solved using only the theory found on Mathraining. Solutions to these problems must be written in , and are corrected by a volunteer. Solutions to problems are deemed correct if they would obtain full marks in a competition. The website also offers virtual tests which gives users a set amount of time to solve a few problems, which are then corrected and given an integer score from 1-7. Problems are divided into 5 difficulty levels, solving them giving 15-75 points based on their difficulty.

Forum

Mathraining offers a forum moderated by administrators for users to discuss mathematics. On this forum users can ask for help with exercises, and there are many marathons, which are forum topics where users post and solve problems. There is also an unofficial Mathraining Discord server