Conjectures are a key component of mathematical inquiry, a process in which the students raise conjectures, refute or dismiss some of them, and formulate additional ones. Taking a design-based research approach, we formulated a design principle for personal feedback in supporting the iterative process of conjecturing. We empirically explored the…

Against the theoretical background of world society and learning challenges related to globalization processes the article deals with empirical findings from two qualitative-reconstructive studies on learning experiences of young people. The first is a study on young people in Germany engaged in child sponsorship programmes for children in the…