This paper describes the techniques for algebraic activity provided by AlNuSet. They have a dynamic and visuospatial nature that makes available tangible images of variable, algebraic expressions and propositions; such images encourage and support the exploration of properties peculiar to these algebraic objects.
The paper shows that the use of these techniques structure a new phenomenological space where algebraic objects, relations and phenomena are reified by means of representative events that fall under the visual, spatial and motor perception of students and teachers. Moreover, the paper show that these techniques can be effectively used in the class to improve the teaching and learning of algebraic concepts.
The theoretical framework of reference of this work is the instrumental approach used by many researchers to analyze the role of CAS in the learning of mathematics. In the paper the instrumented techniques of AlNuSet are compared with those of CAS, highlighting crucial differences for the teaching and learning of algebra.