This Fluency Activity is a part of the Lesson 6, Unit 2, Grade 1. As it relates to addition and subtraction, counting forward and backward by twos affords students review with this strategy. This fluency activity may be challenging for students at first. A Rekenrek helps students visualize numbers and makes it easier for students to change direction as they count. Rekenreks can be made simply and inexpensively with cardboard, elastic, and beads.