Learning Mathematics in Primary Schools is often mediated through the use of multiple representations. However, teachers may not pay enough attention to the way they use these representations. Given that the translations among representations may not always be smooth, it may be insightful to examine how teachers mediate learning through the use of multiple representations. In this paper, I will share key ideas in commognition before I present a case study of how Hannah, a teacher, mediate learning of percentages in her class. I will also introduce the idea of a 'Mediation Flowchart' and demonstrate how it can be used to describe and analyse a teacher's use of multiple representations.