A Microworld for Helping Students to Learn Algebra

This paper describes the design principles of a microworld devoted to the manipulation of algebraic expressions. This microworld contains an advanced editor with classical actions and direct manipulation. Most of the actions are available in two or three modes; the three action modes are: a text mode that manipulates characters, a structure mode that takes care of the algebraic structure of the expressions, and an equivalence mode that takes into account the equivalence between the expressions. The microworld also allows to represent reasoning trees. The equivalence of the expressions built by the student is evaluated and the student is informed of the result. The paper also describes the current state of the implementation of the microworld. A first prototype has been realised at the beginning of February 2001.