In this paper, we dealt with the functions in mathematics teaching, starting with the analysis of functions in the curriculum, school textbooks, and all the way to the matriculation examination. Since the concept of function was already known in the 14th century, a brief history of this concept and definitions that appeared throughout history are given. The basic ideas for the concept of function are described: the idea of association, covariation and object. All the educational outcomes from the curriculum related to the functions are listed, and the textbooks ”Element” and ”Skolska knjiga” from the first to the fourth grade of high school ˇ are analyzed. Each textbook has its advantages and disadvantages, and it is up to the teacher to decide which textbook to use as a teaching tool. The state matriculation exam in mathematics covers tasks from all areas of mathematics, and this paper lists the tasks and results of students from the field of functions. Since motivation is also an important part of teaching, examples are given of how to motivate students for certain topics. In order for teachers to more easily recognize and correct students wrong conclusions or misconceptions, student misconceptions related to functions and methods of determining misconceptions are described