Low achieving eighth graders learn to crack word problems: a design research project for aligning a strategic scaffolding tool to students’ mental processes

Topic-specific didactical design research provides means not only to investigate how to learn but also what to learn, i.e., for specifying learning contents by analyzing students’ comprehension processes in detail. This important characteristic of didactical design research is exemplarily shown for students’ difficulties in finding symbolic expressions for word problems, which can often be traced back to deficits in their comprehension...