While the notion of numeracy as the capacity to make use of mathematics within contexts associated with personal and public life, as distinct from basis mathematical competence, is broadly accepted, forms of professional teacher learning that lead to the effective teaching of numeracy are still the subject of ongoing research. This paper reports on a small scale study which aimed to investigate the potential for pairs of teachers, working with two tertiary mathematics educators, to improve the quality of their teaching of numeracy through reflection on each other's teaching practice. While viewing their teacher pair's lesson via video each teacher identified aspects of the lesson that they could use to improve their own teaching. (Contains 1 figure.) [For the complete proceedings, "Shaping the Future of Mathematics Education. Proceedings of the Annual Conference of the Mathematics Education Research Group of Australasia (33rd, Freemantle, Western Australia, Australia, July 3-7, 2010)," see ED520764.]