In this article, the authors propose that guiding teachers to examine the regulative/discursive norms of school mathematics with tools derived from social semiotics can serve two goals. The first one is to deconstruct the “math is math period!” disposition in prospective teachers by promoting their critical understanding of the symbolic domination work they often unknowingly perform. The second goal is to reconstruct a more socio-political disposition by equipping them with tools for decoding the dominant discursive practices of school mathematics.