Ações de uma formadora no desenvolvimento da agência profissional de professoras em uma Comunidade de Prática.

This paper aims to analyze how teacher trainer's actively supported the professional agency development of teachers, members of a Community of Practice. Therefore, a qualitative research of their participation in the enterprise Numerical Sets Study, with an interpretative slant, was undertaken. The results show that the teacher trainer fostered the study of ideas and mathematical concepts about irrational numbers; encouraged the teachers to work with challenging mathematic tasks; supported them while planning and with the development of a class planed on inquiry based-teaching about irrational numbers. The closeness among the participants, the former and the teachers of the community, affected their professional identities, by valuing their mathematical practice, in order to foster and reinforce their own professional agency. [ABSTRACT FROM AUTHOR]