Derived initially from a strategic analysis of children's methods of counting, the New Zealand Numeracy Projects used, as a starting point for the professional development of teachers, a strategy framework that traces children's development in number reasoning. A pilot study indicated the usefulness of professional development where teachers use the framework to determine the number reasoning of students in their own classes. Subsequently, as part of the professional development offered for the projects, a DVD showing numerous video clips of students was produced to show teachers what range of number strategic thinking they might expect in their classes. In the next five years more clips were added and some edited out. This paper outlines how the video clips were incorporated into the initial stages of the enhanced teacher professional development model to enhance teaching effectiveness in using the strategic number framework, and how these clips are used in the pre-service education of student teachers at the University of Auckland.