This research study aims at exploring the use of some dimensions and theoretical-methodological tools suggested by the model of Didactic-Mathematical Knowledge (DMK) for the analysis, characterization and development of knowledge that teachers should have in order to efficiently develop within their practice. For this purpose, we analyzed the activity performed by five high school teachers, in relation to an activity about patterns suggested in the framework of the Master of Mathematics Education Program at University of Los Lagos, Chile. As a result of the analysis, it becomes evident that teachers can indeed solve items related to the common content knowledge, but have certain difficulties when they face items that aim at exploring other dimensions of their knowledge, for example, about extended content knowledge, of resources and means, or of the affective state of students.