This book is the product of remarkable cultural circumstances that fostered the creation of the so-called mathematical circles, groups formed by students, teachers and mathematicians in the former Soviet Union. It is based on the idea that the study of mathematics can generate the same enthusiasm as practicing a sport with a team that is not necessarily competitive.
So it looks more like a book of mathematical recreations – except it is more serious. Written by researchers teaching mathematics in universities, it is the result of years of experience of these mathematicians with groups of high school students. The sequences of problems are structured so that almost any student can attack the first examples. But the same principles developed in solving problems in the preliminary stages make it possible to solve extremely challenging problems later. Between these two, there are problems of all levels of interest or skill.
