Investigating two trainee teacher educators' transformations of the same resources in technology enhanced mathematics

International audienceWe address the documentational work of two trainee teacher educators in the context of their practicum in an in-service program concerning the use of digital tools in mathematics. Since they drew upon the same existing resources, we investigated the operational invariants – i.e., implicit aspects of their knowledge and epistemology underlying their designs – that influenced and differentiated their documentational work. The identified operational invariants were (a) their focal points during the observation of other teacher educators' classrooms, (b) the constrains and opportunities provided by the educational context, (c) their epistemologies regarding the role of technology in the teaching of mathematics as well as their conceptions of trainee teachers either 'as students' or 'of students'