70 year jubilee of academician Alexei L. Semenov

The article is devoted to the 70th anniversary of Alexey Lvovich Semenov, a prominent Russian mathematician and figure of Russian education. The article provides biographical information and an overview of the professional activities of academician of Russian Academy of Sciences and Russian Academy of Education, A. L. Semenov – both in the fields of mathematics and theoretical informatics, and in other important areas of A. L. Semenov's activity: support and development of school mathematical education, research on issues of the digital transformation of education, upgrading the content of education in primary and secondary schools, as well as professional teacher education.