A wonderful book for the subject of Mathematics.

When a student has finished the curriculum, they are asked to gather in their mind all the methods they have been taught, regardless of when they were taught them. The immediate consequence is that initially, the methods are in an almost "chaotic" form in their mind.

The writing of this book started from the persistent and repeated request of students to be given a set of "methodology keys" with which they could unlock their thinking and understand which "key" corresponds to each exercise.

In the last section, there are review – combinatorial topics of graded difficulty covering the entire curriculum, as well as their solutions.

We believe that this book is a useful assistant for every teacher and an essential companion for every student, especially during the review period.