This Fluency Activity is a part of the Lesson 5, Unit 6, Grade 1. This review activity targets the core subtraction fluency for Grade 1. As students play, closely monitor any students who have not performed well on the core Practice Sets and Sprints to see if they are able to be successful in this untimed, interactive game. Take advantage of any opportunity to highlight improvement. 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.