In the article we compare the approaches of 3 in-service teachers and 3 student teachers when they tried to solve a verbal arithmetic problem in the classroom. Each interaction was studied using a System of Analysis that takes into account the cognitive processes involved in the solution of a mathematic problem and describes the interaction at different levels showing what is done and to what degree teachers and/or pupils are responsible for what is done. The results of the study suggest that both groups of teachers are different in how they direct the student's attention toward the essential aspects implied in the resolution of word problem. On the one hand, the in-service teachers guaranteed students' understanding of the problem before dealing with the solution, while students teachers only did so when pupils committed errors. On the other hand, the in-service teachers allowed a high level of student participation, while student teachers took a more prominent role so children's participation was lower.The importance of sociocultural context in the acquisition of mathematical knowledge is becoming more and more widely accepted. Specifically, educational research assumes that a large part of pupils' mathematics ideas are developed in the interaction between teachers and pupils in communication situations aimed at the acquisition of shared knowledge. In this regard, special attention has been paid to the study of the discourse used by teachers and pupils in classrooms with the object of analyzing aspects that aid the understanding of how maths learning takes place.As we shall explain below, the study of educational practice in general and of discourse in particular has not been carried out in a uniform manner. Our aim in the present article is to