Badr Defouad* (France), bdefouad@magic.fr Instrumentation processes underlying the use of TI92 at high school level During two years, we have been involved in a research project dealing with the integration of the calculator TI92 at high school level. The purpose was to analyse: * the processes underlying the instrumentation of the TI92. * the mathematical knowledge required for this instrumentation. * the articulation between this kind of knowledge and the one expected by the institution. The data include questionnaires, classroom observations, assesments and a biographical study of 9 students. We will focus on the biographical study of the students, presented through the results of two interviews and a specific assesment, particularly on the part concerning a classical task at this level of schooling : function study.