The effectiveness of project-based learning technology has been proven by advanced pedagogical experience, while some aspects of the process of implementing this technology, which is provided for by the Concept of the New Ukrainian School, require clarification and improvement. In the submitted article, the authors present the methodical development of a system of educational projects for the implementation and deployment of the 6th grade mathematics course: «Time Absorbers», «Volunteer Activity», «Journey along the Rivers of Ukraine», «Ukrainian Borscht», «Golden Intersection», «Journey across the Air Ocean», «Green clothes of the plane», «World of professions and mathematics». The system of educational projects is presented in the textbook «Mathematics. 6th grade» (in two parts) by S. Skvortsova and K. Niedyalkova, according to which each section or topic ends with an educational project that has its own topic, purpose and structure. The purpose of each educational project is determined, first of all, by the requirement of the formation of subject mathematical competence, the need to generalize and systematize the educational material. Each educational project developed by the authors has as structural components a motivational component, the creation and setting of a problem situation, advice on the implementation of the project, and reflection. The authors of the article present some results of the testing of the presented methodology; an analysis of the survey of sixth-graders of the Odesa Lyceum «Mriya» who participated in the experiment was conducted. The authors demonstrated that project-based learning allows for the integration of the content of various educational fields based on key competencies, in particular, competence in the field of natural sciences, engineering and technology, information and communication, environmental, cultural competencies, innovativeness, entrepreneurship, and financial literacy, among others. Under the condition of successful implementation of project-based learning, students’ motivation to study the subject improves and the level of educational achievements increases. Keywords: mathematics, basic school, New Ukrainian school, project learning, integrated learning, activity approach, formation of key competencies.