This Fluency Activity is a part of the Lesson 1, Unit 1, Grade 2. By alternating between ten-frame and 5-groups column cards, students develop flexible perception of numbers 6-10 in two parts, with one part as 5. This activity practices the core fluency objective from Grade 1, adding and subtracting within 10. The teacher flashes a ten-frame card for 2-3 seconds and guides students to respond on a signal. Students then generate a number sentence to get to 10.