The book is aimed at middle and high school students with a keen interest in Mathematics and who wish to participate in various competitions. Number Theory is one of the oldest branches of Mathematics and studies the properties and primarily the divisibility of integers. Even today, it is one of the most active branches of Mathematics and has a significant contribution to Cryptography.

The chapters that are thoroughly developed include:

• Euclidean division and divisibility of integers
• Greatest common divisor – Least common multiple
• Prime numbers
• Congruences (modulo)
• Diophantine equations
• Problems covering the entire syllabus

In each chapter, a large number of exercises are proposed, and at the end of the book, brief solutions are provided.

CONTENTS

• Chapter 1: Euclidean division and divisibility of integers
• Chapter 2: Greatest common divisor – Least common multiple
• Chapter 3: Prime numbers
• Chapter 4: Congruences
• Chapter 5: Diophantine equations
• Chapter 6: Problems covering the entire syllabus
• Answers to the exercises