This study seeks to deepen our understanding of the importance of reflection for the development of teaching practice. Research from this perspective - the epistemology of practice - has shown that the exercise of reflection/reflective practice plays a fundamental role in initial and continuing training and in understanding educational action. However, there is little information on the role of reflection in the development of conceptions about maths and its teaching. It starts from the premise that reflection/reflective practice enables the (re)elaboration of conceptions about maths and its teaching-learning process and, in this way, enables new ways of understanding what and how to teach this subject. He points out that the (re)elaboration of conceptions about maths and its teaching is triggered through a cyclical movement, starting with reflection on action and continuing in the moments of continuing education, through collective reflection on the teaching-learning process of this subject.