The inclusion of statistics and probability in the mathematics curriculum has always generated challenges to mathematics teachers of elementary schools. This article discusses activities that promote the professional development of such teachers. We present part of a doctoral research study of 16 teachers in which we discuss two case studies of teachers who planned teaching activities focusing on probabilistic simulations. Results demonstrated that the joint elaboration and discussion, within an educational space marked by collaboration, afforded teachers greater security when addressing the subject, and allowed them to develop new knowledge and ideas on teaching and learning statistics and probability. However, diverse pedagogical beliefs could drive different teachers' attitudes in classes and influence their focus while implementing their practices.