What characterizes good teaching? This question occupies teachers in their daily practice. The authors understand good mathematics instruction primarily as student- and strength-oriented, focusing on content-related and process-related competencies. Important features of instruction aimed at individual learning progress of students also include diagnostic-driven and differentiated learning opportunities. On one hand, the active participation of learners and their assumption of responsibility for their own learning process play a crucial role. On the other hand, the content significance of the learning subjects as well as the orientation towards the learners' content-related concepts and prior experiences are essential elements. This issue presents approaches and formats that help promote the described aspects.