This Fluency Activity is a part of the Lesson 15, Unit 2, Grade 1. This activity builds fluency for subtraction within 10 and promotes an understanding of equality. Assign students partners of similar skill level. Students arrange 5-group cards from 0 to 10, including the extra 5, and place the "=" card between them. Write four numbers on the board (e.g., 10, 9, 2, 1). Partners take the 5-group cards that match the numbers written to make two equivalent subtraction expressions (e.g., 10 - 9 = 2 - 1).