SUMMARY
This article is an excerpt of the Doctoral thesis in progress, in the Graduate Program in Science and Mathematics Teaching (PPGECIM) ULBRA Canoas/Brazil, in order to investigate educational interventions that can be used with a student with Jacobsen Syndrome in order to build concepts and develop their potential as learning Math. The purpose is to understand the student math learning processes, the central research participant, diagnosed with Jacobsen Syndrome, a rare syndrome and limitations in learning. The research methodology consists of a case study performed with monitoring the student trajectory, from regular school to special school. In this article we present a discussion of the data obtained from the analysis of the objectives and descriptive opinions of the fourth year, as well as data on the survey and activities in the first trimester of the Primary School fifth year, aiming the construction of the number concept by the student. However, we conclude that the student failed to relate the number symbol with the number shown without the teacher and assistant mediation with concentration difficulties in carrying out the proposed activities, so that they be taken up constantly in other classes.