Re-engagement means going back to a familiar problem or task and looking at it again in different ways, with a new lens, or going deeper into the mathematics. This is often done by showing examples of student work and providing prompts to help students think about the mathematical ideas differently. This guide provides more information on how to design re-engagement lessons for your students, which you can use at any time during a unit, where you think it will be helpful for students to revisit a specific mathematical idea before moving on.