The topic of this thesis are contents of combinatorics in mathematics classes and a methodical approach to these contents. The search for patterns is one of the main instincts that humanity possesses. Mathematics is often described as the science of patterns, and it can be said that it is mainly concerned with combinatorics, compared to other branches of mathematics. Combinatorics is naturally embedded in the contents of mathematics since elementary school, and its domain is the counting of finite sets. Even in the lower grades of elementary school, students can solve tasks similar to this: "Ema has 2 dresses and 3 jackets. In how many ways can she combine one dress and one jacket that she will wear to go to the theater?" When encountering the students to this type of tasks for the first time, the teacher should successfully lead them to the solution, and then let them find it themselves. Therefore, the teacher should have a good knowledge of the theory that is hidden in the background of such tasks, but should also have the skill of devising new tasks, the solution of which is based on the application of one of the combinatorial principles. This thesis was designed as an auxiliary manual for the teacher in order to introduce combinatorial concepts in the lesson as naturally as possible and to stimulate students' motivation and interest in these contents. The first analyzed teaching content is the basic principles of counting: the principle of multiplication, the principle of sum, the principle of difference and the principle of quotient. For each of the mentioned principles, examples of introductory tasks for teaching are given with a detailed call for solutions. In addition, the concepts of variation, permutation and combination with and without repetition and the binomial formula are defined. In addition to the definitions, teaching activities are listed, that is, tasks that clearly present the mentioned concepts. The learning outcomes that are realized by adopting teaching content from the field of combinatorics and an example of the schedule of teaching hours are also listed.