Based on the notions of social and socio-mathematical norms we investigate how these are established during the interactions of pre-service teachers who solve mathematical problems. Norms identified in relevant studies are found in our case too; moreover, we have found norms related to particular aspects of the problems posed. Our results show that most of these norms, once established, enhance the problem-solving process. However, exceptions do exist, but they have a local orientation and a relatively small influence. (Contains 3 figures and 3 notes.)