The article substantiates the didactic conditions for the effective formation of key competencies of high school students in learning the disciplines of the natural and mathematical cycle. The authors consider how to give the content of training a competence orientation by offering tasks of different complexity levels. They also substantiate that the modular organization of the learning content affects the competence growth of high school students. In the article, the authors describe how experimental training was planned and carried out within the framework of conducting the optional course “Fundamentals of Cognition in Education” which allowed to test and verify the effectiveness of the specified didactic conditions.