This article documents the phenomenon related to the difficulties encountered by some students to articulate the senses assigned to different representations of a mathematical object obtained by semiotic transformations of treatment. It is presented a description and an analysis of the process of assigning senses achieved by students regarding specific tasks, where is required making such treatments between representations. This paper is situated in a semiotic context, and studies in general the relationship semiosis-noesis in the construction of mathematical knowledge by students from grades 9th and 11th of the secondary education (Colombia); this study, without being exhaustive, includes aspects of mathematical activity, communication of mathematical objects emerging and cognitive construction of mathematical objects.