There is broad agreement that the choice of mathematical examples is central to the teaching of mathematics and that a teacher's choice of examples may either facilitate or impede learners' understanding. From this starting point it can be deduced that programmes of instruction for teachers should include the study of mathematical examples. However, there is much to learn about the kind of professional development that might support beginner teachers in the careful choice of examples. This paper presents a case study of a group of sixteen students on a one-year Primary PGCE (5-11) programme who met each month over the first six months of their course to consider example sets. The research events explored how student responses to examples presented in textbooks changed over time. The outcomes of this study suggest that over time students noticed more about opportunities for generalisation and progression in the mathematical constructs explored in the example sets. Students also noted many of the pedagogical concerns associated with textbook use. The outcomes of this study lead to the recommendation that programmes of instruction include explicit opportunities for beginner teachers to generate, explore and reflect upon examples for real or hypothetical classroom situations.