"Mathematical Competitions ." Arithmetic and Algebra by Evgeny Borisovich Dynkin is a fascinating and informative work that will become a real treasure for all lovers of mathematics, as well as for those who seek to develop their analytical abilities and logical thinking. Dynkin, a well-known Russian mathematician and teacher, offers readers a unique approach to the study of arithmetic and algebra through the prism of mathematical competitions. This is not just a textbook, but a real find for those who want to deepen their knowledge and prepare for the Olympics and competitions. The book contains tasks that will help readers not only to master the basic concepts of arithmetic and algebra, but also to learn how to apply them in non-standard situations. Each task is accompanied by detailed solutions and comments, which allows not only to find the answer, but also to understand how they came to it. This makes the book ideal for high school students, students, as well as anyone interested in mathematics at a deeper level. The topics raised in the book cover a wide range of issues, from simple arithmetic operations to complex algebraic equations and inequalities. Dynkin pays special attention to methods of solving problems, which allows readers to develop critical thinking and a creative approach to mathematics. It shows how different strategies can be used to solve the same problem, making the learning process more fun and diverse. The book will be especially interesting for those who are ready for intellectual challenges and want to test their strength in solving non-standard tasks. It is suitable for both students seeking success in mathematical Olympiads, and for students who want to deepen their knowledge in the field of algebra. In addition, the book will be useful to teachers who are looking for new methods for teaching their students and want to inspire them to study mathematics. Dynkin's style is distinguished by clarity and accessibility, which makes complex mathematical concepts understandable even for beginners. His previous works, such as “Tasks in Mathematics for Schoolchildren” and “Mathematics for All”, have also been recognized for their practical focus and fascinating approach to learning. In "Mathematical Competitions", the author continues this tradition, offering readers not only tasks but also fascinating stories related to mathematics, which makes reading the book even more interesting. This book will be a great help for anyone who wants not only to learn mathematics, but also to love it. It inspires learning and opens new horizons in understanding arithmetic and algebra. If you are looking for how to improve your math skills, or want to prepare for the Olympics, "Mathematical Competitions. Arithmetic and Algebra” is what you need. Do not miss the opportunity to immerse yourself in the world of numbers and formulas with Evgeny Borisovich Dynkin - your guide on a fascinating journey through mathematical competitions!