This paper refers to an investigation of a teacher's own practice, in mathematics classes, with the use of exploratory-investigative tasks. The research was carried out with high-school first graders at a public state school in São Bernardo do Campo, São Paulo, in 2005. It is aimed at analyzing knowledges revolved and incorporated by the teacher-researcher. Initially, the text brings a discussion about this research mode and the relevance of using exploratory-investigative tasks. The analysis is centered on (audio-recorded) episodes which focused on the teacher-researcher's mediation/intervention while students were working. Special attention was given to the importance of others (students, pairs and research mates), which causes some reactions of surprise and questioning, besides leading to reflexive processes. At last, it brings an analysis of the conflicts aroused by the contiguity of the teacher's and researcher's roles in a classroom environment.
Professional knowledges; Investigating one's own practice; Exploratory-investigative tasks
