International audienceThis article reports on research focused on the integration of a specific computer tool, the spreadsheet, into mathematics teaching. After presenting some important results obtained by research in this area, we revisit these in the light of an instrumental approach, which we perceive as essential to analyse the construction of mathematical meanings in spreadsheet environments and to understand better the questions of technological integration. Then, these theoretical elements are used in order to design an exploratory experiment with grade 7 pupils and analyse its results

International audienceThe chapter briefly introduces the Theory of Didactical Situations (TDS) by referring to the data from Chap. 2. TDS provides a systemic framework for investigating teaching and learning processes in mathematics, and for supporting didactical design. The theory is structured around the notions of a-didactical and didactical situations and includes a corpus of concepts relevant for teaching and learning in mathematics classrooms

Abstr act: The spreadsheet is not a priori a didactical tool for mathematics education. It may progressively become such an instrument through the process of professional geneses on the part of teachers. This chapter describes the beginning of such a genesis, and presents some results concerning teachers' professional development with spreadsheets by examining the outcomes of two different sets of data. Theoretical notions, such as instrumental distance and double instrumental genesis supported the analysis of data leading to a comparison of a teacher who is integrating spreadsheets for the first time in her practices with the practices of teachers who are more expert with spreadsheets. The similarities found in the ways they use the tool leads to some hypotheses on the importance of these common elements as key issues in teachers' ICT practices.K eywor ds: mathematics teaching and learning, teaching practices, ICT integration, professional learning of mathematics teachers, technology-mediated classroom practices, spreadsheet, professional/ personal instrument, double instrumental geneses (professional/ personnal), instrumental distance, novice/ expert teacher lack of material; conservatism etc. Without denying these factors, my research claimed that there are deeper reasons for teachers' resistance, related to the impact that technology has on the mathematics to be taught, and the difficulty, for teachers in managing this impact. Therefore, it remains important to advance our understanding of this impact and the ways that teachers account for it.With this purpose in mind, this chapter aims to provide an insight into teachers' practices with technology by comparing the results of different studies concerning the same technology, the spreadsheet (Haspekian 2005a, 2011). The first two studies formed different parts of my doctoral study. These were an observation of a teacher, called Ann 1 , who was integrating spreadsheet for the first time in her practices and an inquiry interviewing and comparing pre-service teachers with teachers who were "experts" with spreadsheets 2 . The third study resulted from another research proj ect, which observed ICT sessions in ordinary classrooms, during which I happened to return to Ann's classroom. Thus, I had the opportunity to observe her practice a year later. Hence these studies provide an opportunity to make an interesting comparison concerning teachers' practices with spreadsheets at different stages of integration: