In this math meets physics lesson, learners encounter the magical effect of reflection as they use a mirror to visually experience the concept of doubling quantities. This experience focuses learners' attention to using doubles as a strategy to make number operations easier, specifically addition. The book "Two of Everything" by Lily Toy Hong is used to introduce learners to these concepts. A game is used for discovery and practice and writing is used as closure to this lesson. This lesson guide includes questions for learners, assessment options, extensions, and reflection questions.