A mathematics classroom can be thought of as a “little institution” with a distinct repertoire of things that can be done and said. What is counted as an intelligible instance of the social practice in a mathematics classroom is a function of the rules, norms and principles to which the participants’ actions conform. These are in operation at many different levels and have been analysed and conceptualised, for example, as “classroom social norms”, “socio-mathematical norms”, “meta-discursive rules”, as features of the “didactical contract”, or as a “code” to be “cracked”.

By definition, any “rules” of a social group and their practice are public, but this does not mean that the students and their teacher are consciously following the rules that constitute their actions in the mathematics classroom. However, for successfully taking control over their participation in a mathematics classroom, students need to know what may be talked about and how it is to be talked about, what is seen as appropriate behaviour, they need to understand the evaluation criteria and engage with the pace.
Studies of mathematics classroom practices show that many “rules” remain tacit and that not all “rules” of a mathematics classroom are equally accessible to all students. The talk will focus on conceptualising students’ struggles of uncovering “hidden rules”. In order to understand how some students more easily become competent members of a mathematics classroom (while others do not), classroom practice has to be interpreted from a perspective that transcends a reconstruction of the intentions of the participants. Possibilities of developing a language of description that accounts for the construction, maintenance or mitigation of unequal attainment on the micro-level of classroom practice will be discussed.