The article discusses the results of some studies of distance learning. Distance learning has developed rapidly due to the coronavirus pandemic. The forced use of this form of education has shown that teachers are not ready to work in such conditions. The main advantages and disadvantages of using distance learning, the main areas of using the experience of their application in the post-pandemic period are analyzed. The development of distance learning stimulates the development of open education as a modern phenomenon. The need and demand for affordable, free education is ensured by the use of electronic distance courses based on modern learning management systems with strict regulation of the content and process of learning. At the same time, open education provides students with the freedom to choose the time and place of study. The article provides an analysis of modern domestic open education resources available for use in teaching mathematics to schoolchildren, using the capabilities of developing digital technologies in lessons and extracurricular activities in mathematics. The Russian Electronic School, Sferum and others are considered as the main domestic platforms. The first of the named platforms was developed within the framework of the departmental target program of the Ministry of Education and Science of the Russian Federation “Russian Electronic School”. The capabilities of the most common software tools in activating the educational and cognitive activity of students and increasing the level of subject knowledge are also shown.