The number rack helps build the bridge from counting to computational fluency by inviting students to think about numbers in groups of 2, 5, and 10. Its 2 rows of 5 red and 5 white movable beads allow students to see and slide beads in groups rather than 1 by 1. Just as we want students to move from sounding out words letter by letter to reading morphemes and whole words, we want students to move...