The teaching of algebra has captured the attention of researchers in mathematics education in such a way that the discussion on this topic has promoted different interpretations regarding the origin and its socially diffused learning. In this sense, working with all points of view regarding algebra, would lead to study and conceptualize this particular way of mathematically pondering, in addition, to consider its construction from the development of thought and algebraic reasoning. Consequently, the analysis of the concepts of the letters or alphanumeric symbols in expressions such as the equations, which has been done in years of research, constitutes one of the main concerns in this field, however, it does not lie only in the adherence of new signs or representations to the techniques and schemes that students already have, but to the previous development of the elements that make up a structured language, which refers to abstract objects and the way of reasoning with them.