This Fluency Activity is a part of the Lesson 3, Unit 6, Grade 1. This review activity strengthens students' ability to subtract within 10, which supports their work decomposing numbers in future lessons within the module. Students combine their digit cards and place them facedown between them. Each partner flips over two cards and subtracts the smaller number from the larger one. The partner with the smallest difference keeps the cards played by both players in that round. If the differences are equal, the cards are set aside, and the winner of the next round keeps the cards from both rounds.