The best Olympiad tasks in mathematics. Grade 10-11

The proposed manual discusses various methods and techniques for solving olympiad problems of different levels of difficulty for students in grades 10-11. The tasks presented in the book are devoted to such classical topics as divisibility and remnants, invariants, diophanta equations, the principle of airships, geometric tasks, etc. Answers and instructions are given to all tasks, and the most difficult solutions are given, and some problems are solved in various ways. Most tasks are copyrighted, marked by the icon (a) The manual is primarily intended for high school students of secondary schools, lyceums, gymnasiums, mathematics teachers to prepare children for Olympiads at various levels, as well as for the exam, students - future teachers, employees of additional education centers and all fans of mathematics