The purpose of this paper is to examine trainee primary school teachers' confidence in their mathematical content knowledge (MCK) and confidence to teach specific primary mathematics concepts (mathematics pedagogical content knowledge --MPCK) which was correlated to their actual MCK on specific tasks. For this correlational study survey and test data were collected from a cohort of 210 trainee teachers. It was found that confidence to do and to teach mathematics was reasonably strongly correlated with competence. Trainee teachers' confidence varied greatly depending on the specific mathematics they were attempting. When presented with specific tasks, trainees were well aware of the link between personal numeracy levels and their potential to teach primary mathematics. A further finding was that the trainee teachers tended to over report their confidence. It is unknown if this is a cultural manifestation or a limitation of the scale. The data also add to the body of knowledge with respect to the MCK of about-to-graduate primary teachers.