This book is mainly based on the test and selection questions of the 2024 Chinese National Training Team. It compiles the problems and solutions of major domestic math competitions held from August 2023 to July 2024, as well as those of the 2024 International Mathematical Olympiad. Additionally, it includes the problems and solutions of the 53rd American Mathematical Olympiad, the 50th Russian Mathematical Olympiad, the 15th Romanian Master of Mathematics Competition, and the 13th European Girls' Mathematical Olympiad in 2024. Most of these problems are carefully crafted by experts engaged in mathematical Olympiad teaching and research. Some of the solutions are provided by members of the Chinese National Training Team and the national team, whose ingenious and elegant approaches have greatly enriched this book.