This Fluency Activity is a part of the Lesson 10, Unit 6, Grade 1. In this fluency activity, students apply their knowledge of partners to ten to find analogous partners to multiples of 10. Students need this skill when they learn to apply the make ten strategy to add two two-digit numbers in Lesson 13. Model with the Rekenrek for the first few problems. Then, put the Rekenrek away to give students practice mentally getting to the next ten.