Focusing on the environment of learning of a PD course and on teacher's classroom work, the aim of this study was to find links between what teachers learned about Mathematical Thinking Activities (Wiskundige Denkactiviteiten - WDA) with their work in classroom. Therefore, the study attempted to identify similarities, changes or empowerment on teacher's pedagogical content knowledge (knowledge about how to teach a subject) and teacher's professional competence (person's ability to transfer knowledge into action) (Maass, K.; Doorman, M.; pg. 890; 2013). In order to carry on the research, the...