This dissertation aimed to investigate the knowledge mobilized to teach mathematics of graduates of the same Pedagogy course working in the early years, as well as to understand how personal and formative trajectories interfere in the professional action of teachers when referring to the teaching-learning of mathematics. Teaching mathematics to students in the early years requires a lot of knowledge involved and is built throughout the teacher s life trajectory. Tardif, Charlot, Hosfstetter and Schneuwly, Valente, and others were used as theoretical references about teaching knowledge. García helped in the understanding of teachers development and professional trajectory along with the discussions present in Nóvoa and Gatti s works about professionalization. Roldão also contributed by discussing professional knowledge, among other studies that could add to the theme. Through qualitative research, this study used the questionnaire and the interview as methodological tools. Of the 60 questionnaires answered, 16 corresponded to the selected profile, and 13 graduates agreed to participate in the interviews. Among them, seven worked in private schools, four in the municipal network, and two in the federal sphere. The results pointed to the mobilization by the teacher of three sets of knowledge: student knowledge, formative knowledge, and institutionalized knowledge. The human and critical formation of the Pedagogy graduate was highlighted as a positive point. As a point of attention, it is still possible to observe gaps concerning the mathematical contents to be taught and a lack of approximation between theory and practice, pointed out by the interviewees as a difficulty when arriving at school.