In this article, the authors present a writing activity that allowed pre-service teachers to be creative in the mathematics classroom. Inspired by "The Important Book" by Margaret Wise Brown, students explored secondary-level mathematics concepts, discussing various attributes/characteristics of each concept through their written contributions. Although these were pre-service teachers, the authors argue that this activity would be equally successful in a secondary mathematics classroom. In particular, this activity can increase engagement of disengaged students, support students for whom English is an additional language or dialect (EAL/D), and address the literacy general capability of the "Australian Curriculum."