1.OA.C.6 Fluently Adding and Subtracting Within 20, Fluency within 10. Activities in this packet will provide support for students as they add and subtract within 20, being fluent within 10. Strategies are essential for conceptual understanding and procedural fluency. The activities included here are to provide effective practice along with recording student growth through self– or teacher monitoring. These activities are great for small group, guided math, centers, RtI, extended learning and whole class practice.