This paper explores tensions between the teacher's intention and the students' interpretation of a reformed classroom practice. Focus for this paper is particular on the social and socio-mathematical norms. The example presented in the paper is connected to the use of resources, such as manipulatives, to catch both explicit and implicit tensions between the students' perceptions of existing norms and teacher ' s intention of supporting norms. These tensions could form and cause a barrier to students' opportunities to learn. Reform teaching is likely to fail if students do not share a similar understanding to that of their teacher in regards to their contribution to mathematics learning.