This Fluency Activity is a part of the Lesson 13, Unit 6, Grade 1. Careful selection of pairs for collaborative work is essential to achieving expected outcomes. Some lessons lend themselves to groupings of students with similar skill sets, while others work better when students are heterogeneously grouped. Some students benefit from the opportunity to work independently and share with the teacher or another pair after they have completed the task. This fluency activity reviews how to use the Level 3 strategy of making ten to add two single-digit numbers. Reviewing the make ten strategy prepares students for today's lesson, in which they make ten to add two two-digit numbers.