In this article, the author describes a task given to pre-service secondary school mathematics teachers. By exposing them to a relatively simple mathematics process, it was hoped that their ability to plan and implement lessons for their own students would be enhanced.

Addresses the definitions of several mathematical concepts and the relationships between them based on a theoretical framework presented in the first part. Presents two examples of mathematical activities on equivalent and non-equivalent definitions constructed in the context of professional development workshops for mathematics teachers.…

Presents a mathematics activity that illustrates how such adjectives as elegant, surprising, concise, and challenging can be, and in fact are, attributed to proofs by a not very expert audience. (ASK)