This paper discusses results from a design research in line with Realistic Mathematics Education (RME). Daily cycles of design, classroom experiments, and retrospective analysis are enacted in five days of working about division by fractions. Data consists of episodes of video classroom discussions, and samples of students' work. The focus of discussion and analysis centres on the role of contexts and the role of teachers' probing questions to elicit students' thinking. Our findings suggest that contexts that are meaningful for and understandable by students bring out rich mathematical thinking and discussion amongst students. Meaningful contexts combined with teacher's probing questions--highlighting big mathematical ideas--allow students to attain various approaches at different levels of formal mathematics. (Contains 1 table and 9 figures.)