Our approach to the study of emotion in school mathematics draws on several theoretical strands, all of which give a central role to the notion of discourse. Thus, emotions are considered as socially organised and shaped by power relations. We see emotion as analytically distinct from cognition, but at the same time as inseparable from it in practice: metaphorically we portray emotion as a charge (of energy) attached to ideas or (chains of) signifiers. To develop these ideas, we analyse a verbal text, based on a video record of a small group of students solving mathematical problems. The structural phase of the analysis identifies the positions available to subjects in this specific field; here we isolate five available pairs of student-positions, which can be inter-related using Bernstein's (2000) sociological approach to pedagogic discourse. The textual phase examines the use of language and other signs in interaction and describes the positionings taken up by particular pupils. Developing the textual phase, we then focus on indicators of emotion, drawing especially on psychoanalytic insights. Here we find indications of a range of emotions such as excitement and anxiety that may be linked to participants' positionings. We conclude by considering some theoretical, methodological and policy implications of our approach.