Abstract
We present findings made during the first cycle of an ongoing design research study on the working out of basic multiplication in 8 Austrian classes. Their teachers had tried to implement an instructional design that put conceptual understanding and derived facts strategies centre stage. Focusing on the degree of fact mastery reached at the end of grade 3, we present a typology of strategy use within a sample of 48 students. We take a closer look at lower-achieving students, in particular those 8 students who had little if any success in mastering basic multiplication. While 6 of them used derived facts strategies quite often, deficiencies either in adding and subtracting or with regard to the conceptual basis of those strategies seem to have hindered them from mastering more facts. Implications for the forthcoming second cycle of the study are discussed.