We present a new software, called Goluca (Godinho, Luengo, and Casas, 2007), based on the technique of Pathfinder Associative Networks (Schvaneveldt, 1989), which produces graphical representations of the cognitive structure of individuals in a given field knowledge. In this case, we studied the strategies used by teachers and its relationship with the perception expressed about their own abilities for mental calculation. First of all, the participants, 14 primary teachers, were asked what opinions they had about their own capabilities of mental calculation, classifying them as good, bad or moderate. Using the software Goluca, representations were obtained in the form of Pathfinder Associative Networks and the cognitive structure of these teachers concerning to the mental calculation strategies they used and calculated the consistency of such networks, denoted as "coherence". The results obtained allowed to identify which were the main strategies used by teachers and specify that teachers, who feel they have good skills in mental calculation, have more consistent cognitive structures. (Contains 2 tables and 5 figures.)