This book is aimed at students of the natural sciences, mathematics teachers, and participants in ASEP and Olympiad competitions.

It is a comprehensive treatise on classical Number Theory. The theory is developed thoroughly and is complemented by a wealth of examples and applications that clarify all the concepts in detail.

It includes the following chapters:

• Euclidean division of integers
• Divisibility of integers
• Greatest common divisor - Least common multiple
• Prime numbers
• Congruences
• Arithmetic and multiplicative functions
• Polynomial congruences and quadratic residues
• Diophantine equations

In each chapter, a large number of progressively difficult exercises are proposed for solution, for which brief solutions or hints for their solution are provided at the end of the book.

- For students of natural sciences
- For mathematics teachers
- For ASEP and Olympiad competitions