This article discusses the problem of implementing interdisciplinary connections between a school course in Mathematics and other natural science disciplines at a secondary school as topical means of developing functional literacy among pupils. The mechanisms of interdisciplinary connection of Mathematics with other disciplines are listed. As a means of interdisciplinary communication of Mathematics with other disciplines, there can be the interaction of pupils in the information educational environment to search for new knowledge, to identify properties of a generalised character, to solve practice-oriented problems, to combine knowledge from various general education subjects, to teach Computer Science based on the transfer and generalisation of knowledge from related subjects. The article provides examples of practice-oriented tasks that illustrate the relationship of Mathematics with such secondary school disciplines as Computer Science, Biology, Geography, and Physics. It is noted that when solving such problems, schoolchildren learn various aspects of multi-level practice-oriented activities, including the use of computer capabilities and the global Internet. It is shown that mathematical constructions and their analogues are found even in areas of knowledge quite distant from exact sciences, such as literature, for example. It is substantiated that it is the solution of interdisciplinary problems that forms the meta-skills necessary for everyday life in pupils.