In some concentration subjects of online programs, such as theoretical scientific subjects (Mathematics, Physics, etc), where most of the problems have only one solution and there are few chances for discussion, the development of transversal skills, such as team-working, leadership, or oral and written expression is forgotten. Typically, only specific competences about the subject are acquired. Due to the lack of discussions, students usually work in an autonomous way, only a few days before the exam, and this causes a high ratio of desertion. To avoid this, teamwork has been planned. In it, lecturers and students assess the correctness of the solutions, the presentation of the reports, the written expression, the pedagogical quality of their explanations, and some teamwork skills such as organization, distribution of the work, the use of e-learning tools for communication, etc. To collect and analyze the marks which students grade each other's work a simple tool has been created. This way, in a preliminary analysis it is shown that students are closer to their mates, they develop transversal skills, and they study during all the year, increasing the ratio of success.