Hill, Rowan and Ball (2005) define mathematical knowledge for teaching as the mathematical knowledge that the teacher applies during teaching. Ball et al. (2008) identify two domains of mathematical knowledge for teaching, namely subject matter knowledge, and pedagogical content knowledge (Figure 1). The domain subject matter knowledge consists of three categories, namely: 1) common content knowledge; 2) knowledge at the mathematical horizon; and 3) specialised content knowledge (Ball et al., 2008). Pedagogical content knowledge, on the other hand, entails three categories, namely: 1) knowledge of content and students (learners); 2) knowledge of content and teaching; and 3) knowledge of the curriculum.