Great for supporting the development of number sense rekenreks are visual models that encourage students to subitize think of numbers in groups strengthen counting proficiency develop addition and subtraction strategies and gain a better understanding of number relationships. Use the Two-Bar Student Rekenrek to practice numbers up to 20. This unit features a wooden frame 2 metal bars with 5 red beads and 5 white beads on each and a dry-erase removable blocking panel. The panel attaches to the rekenrek on the right and can be used to write equations or to hide beads from view. Rekenrek measures 10 3/4" L x 2" W 2" H when the blocking panel is in place. Panel measures 51/2"L x 3" H.