Abstract : Within the theoretical framework of Vygotsky's theory, the paper presents a new algebra software. The main features of the software are described and their potentialities are discussed. According to the Vygotskian theory, expressions and commands may be thought as external signs of the Algebraic theory, and as such, they may become instruments of semiotic mediation: In other terms they can be used by the teacher, in the concrete realisation of classroom activity, according to the motive of introducing pupils to syntactic manipulation as a theoretical activity.