This Fluency Activity is a part of the Lesson 21, Unit 1, Grade 1. Counting on allows students to maintain fluency with this strategy as they solve addition problems. Students sit in a circle and count by ones, each student saying one number to count up. When a student says an even number, she stands: 1, 2 (student stands), 3, 4 (student stands). Continue around the circle until all students are standing.