This textbook contains material on two different, albeit closely related scientific disciplines - mathematics and computer science. Mathematics, one of the oldest sciences, has the widest application in all spheres of human activity. It can be said that without the achievements of mathematics there would be no modern civilization. In turn, computer science today is almost the most developing science, which is at the forefront of social progress. The textbook includes the applied achievements of the authors, examples of the use of classical methods and tasks for independent work of students, questions for self-testing . The material of the textbook can serve as a basis for the use of formal methods for solving practical problems. For students of higher educational institutions studying in the areas of preparation "Economics" and "Management" .