This text is designed as a course of mathematics for higher technical schools. It contains many worked examples that illustrate the theoretical material and serve as models for solving problems. The first two chapters "Number. Variable. Function" and "Limit.  Continuity of a Function" have been made as short as possible. Some of the questions that are usually discussed in these chapters have been put in the third and subsequent chapters without loss of continuity. This has made it possible to take up very early the basic concept of differential calculus—the derivative— which is required in the study of technical subjects. Experience has shown this arrangement of the material to be the best and most convenient for the student.