A one year project was started in the school year 2003/04 to test the use of symbolic calculators (SC)--the TIVoyage 200--in six 10th grade classes of three grammar schools in Bavaria (Germany). The project was repeated in school year 2004/05. The evaluation of the project was intended to give answers to the following questions: how basic mathematical skills (algebraic transformations, solving equations, working with tables and formulas) changed; how the questions posed in examinations changed if the students were allowed to use a symbolic calculator (with CAS); how the students evaluated the use of the new tool; and how teaching styles and methods changed in the mathematics lessons. This article presents the results of this project. (Contains 18 figures and 1 table.)