The aim of the article is to present the benefits of cooperative learning in mathematics in distance teaching conditions during the COVID-19 pandemic. In longitudinal studies, six math teachers formed a collaborative network and developed scenarios for three projects to be implemented by students on an educational platform. During their eight-week implementation, the principles of cooperative learning, using the methodical implications of the self-determination theory (SDT) have been followed. Mathematical problems were solved using the capabilities of the Teams platform. Among students (N = 104) from five sixth grades of primary school who took part in the study, measurements of social-emotional skills were carried out using the Distance Learning Climate questionnaire (DLC-21), designed for the study. The students have shown a high level of mathematical performance (84.8%), the significant increase of the relatedness to the group and the significant decrease in a sense of situational fear. The results also indicate a high level of students' sense of competence and satisfaction associated with the implementation of mathematical projects. The obtained results should be included in further research on the effectiveness of distance mathematics teaching methods.