Ideias matemáticas na prática de um serralheiro: contexto para o ensino de matemática

This work is in charge of presenting the results of a research that aims to understand mathematical ideas mobilized in a locksmith’s practice that can constitute a context for teaching school mathematics. The research subject is a locksmith with 29 years of experience. The research of a qualitative type with the contribution of ethnographic research. For data colletion, observation, interview and photographic record were used. Data analysis was performed using the triangulation method. The results obtained allow us to affirm that is the constext of the lochsmith there is a mobilization of mathematical ideas in the construction of grids and in the work instruments called templates. Such ideas are related to mathematical content taught in Basic Educacion, both in Elementary and Secondary Educacion, which can be used by the teacher as a context for teaching mathematics.