This book is aimed at students in the 5th and 6th grade of primary school who wish to participate in the "Game and Mathematics" competition of the Hellenic Mathematical Society (HMS) as well as in other competitions, such as "Kangaroo". This book also aims to be a valuable aid for the Mathematics of students who will take part in the entrance exams for the Model Junior High Schools.

The book is divided, by thematic unit, into paragraphs with complete theory, examples, solved applications for better understanding of the concepts, and development problems for the consolidation of these concepts. At the end of the book, the solutions to the problems contained in it are provided, as well as previous competition topics of the HMS (together with their solutions). Also included are the Mathematics topics (together with their solutions) of the entrance exams from 2013-2018 for the admission of students to the Model Junior High Schools.