The aim of this work is to investigate professional knowledge (PC), in particular didactic knowledge, in the areas of curriculum knowledge and the training process, to understand professional development (PDs) and the factors that develop it, and to study the relationship between the PD of knowledge of itself, the development of new professional skills and awareness of aspects of its CP, and also to see that new technologies (NT) have important implications for the teaching of mathematics. They do not involve minor alterations in the traditional ways of working the various topical ones, but they provide a profound change in objectives and practices. Their continued use makes it possible to bring mathematics closer to other subjects of education and life, to raise the interests of pupils and to increase and diversify teaching and learning activities. The perspective is taken that the teacher is a competent and responsible professional, who has a fundamental role to play, possesses his/her own knowledge and ability to reflect and act in practice. The methodology adopted, of a qualitative nature, includes observation of classes, team meetings, conducting interviews and questionnaires, reflections on classes and meetings and building narratives. The analysis of the data was based on the theoretical budgets of the study and the categories defined on the basis of a comparison of the data collected with those budgets, and had an impact on the main aspects of the role of the teachers involved in the study, namely: create conditions for the development of activities; pre-empting the activity; supporting the activity; promote the development of the research process; demonstrate the nature of the research activities; promote communication and development of concepts and procedures.