The necessity of using inquiry-based learning (IBL) was recently recommended by studies and reports made for the European Commission. Several European projects are devoted to the widespread use of IBL methods. The effects of using IBL are studied worldwide. In the framework of the Seventh Framework Program (FP7) project PRIMAS, a series of piloting activities were organized in Romania in order to test, adapt and develop inquiry-based teaching materials. Most of these piloting actions were organised by local professional communities with the purpose of creating real feedback for the project and for gathering professional experience in implementing inquiry-based pedagogies in mathematics and science education. This article presents an activity where students were formulating the problems. Teachers were only creating the milieu and facilitating the work. As a second step, the accumulated experience related to this activity was used in a professional development (PD) course organised by the Babes-Bolyai University in the framework of the PRIMAS project. (Contains 10 figures and 1 footnote.)