摘要：This article describes the cross-referenced results of two educational experiments on the use of social platforms in the teaching and learning of mathematics. These were conducted over the course of two years in two mathematics courses at secondary schools in the Campania region of Southern Italy and in two courses of Calculus at University of Salerno, in the south of Italy. It aimed to highlight the role that the teacher assumes in online discussion, revisiting their role as a transmitter of knowledge and taking on the role of facilitator in the acquisition of skills. The qualitative results seem to point to significant benefits in the processes of evolution in the use and coordination of semiotic representation systems. Thanks partly to the help offered by the teacher, the peer comparison between enhanced the transition both from common to evolved language and from interpsychic to intrapsychic functions, i.e. the transition from forms of social activity to forms of entirely individual activity.
