This Fluency Activity is a part of the Lesson 18, Unit 5, Grade K. Manipulating their own Rekenreks allows students to work at a comfortable pace. Saying "buzz" at the end of each row delightfully draws attention to the grouping of ten on the Rekenrek. Put your Rekenrek together with your partner's. Whisper count with your partner up to 40 on your Rekenrek. Take turns moving the beads with each new row.