Improving pre-service teachers’ content and pedagogical content knowledge on rational numbers. In F. Depaepe (chair), Pre-service and in-service teachers’ professional knowledge: Diagnose, intervention, and change. Symposium conducted at the biennial conference of the European Association for Research in Learning and Instruction (EARLI)

The rational number domain is typically a difficult curricular domain for elementary school students. To appropriately deal with students’ difficulties, teachers need well-developed content knowledge (CK) and pedagogical content knowledge (PCK) in the rational number domain. Unfortunately, recent studies revealed serious gaps in (pre-service) teachers’ rational number CK and PCK. We conducted an intervention study with a pretest-posttest design addressing CK and PCK on rational numbers. In an experimental condition 142 pre-service teachers participated in a 14h lesson series on (teaching) rational numbers. The pillars of the lesson series were: (1) emphasizing students’ misconceptions about rational numbers, (2) introducing a broad range of instructional strategies and representations to teach rational numbers, and (3) fostering a close connection with regular classroom situations. The control condition, in which 138 pre-service teachers were involved, consisted of a traditional 14h lesson series on (teaching) rational numbers, differing from the experimental lesson series with respect to the three pillars. The results revealed that the growth in pre-service teachers’ CK and PCK was significantly higher in the experimental than in the control condition. We discuss the implications of these results from both a scientific and educational point of view.status: publishe