The study of operations, as a scientific discipline and practical methods, is focused on solving practical problems that can be correctly described using a particular mathematical model in order to obtain an optimal solution. This book can serve as a textbook on the theory and practical application of operations research methods. Each topic begins with introductory material available to primary students, then the level of presentation of each chapter gradually increases and is designed for senior students. At the end of each chapter, a set of complex tasks related to the topic is presented, which significantly deepen and expand it.