This book is addressed to 3rd year high school students (Positive orientation), but also to fellow Mathematicians (given that it includes a large and original collection of exercises). It is written based on the new syllabus provided for this class. Includes the chapters Tables - Linear Systems and Complex Numbers. At the end of each chapter there are approximately 200 solved exercises and theory comprehension questions. A special appendix contains solved general application problems of the respective theory.

Emphasis is placed on exercises unknown in the Greek literature and on subjects of various exams and competitions (French Baccalaureate , exams of the Universities of Cambridge , London , Oxford , Moscow , Bucharest , etc., G. Putnam competition, Olympiad competitions, E.M.E competitions etc. ) .