Transparent Rule Based CAS to Support Formalization of Knowledge

The complexity of computer algebra systems hinders many students to develop an adequate mental model of such a system. As a result, they are often suspicious about the results and the didactical benefit is limited. The paper suggests that it is possible to design a transparent version of a computer algebra system that gives students a transparent access to the inner working of such a system. Didactical uses of such a system are discussed.