The Rekenrek, or abacus, helps children build an understanding of number values and number representation. This math manipulative supports little learners, from preschool through kindergarten, as they explore early addition and subtraction concepts. This set includes 25 mini 20-bead Rekenreks, ideal for a full classroom. Size: 34.3 x 30.5 x 8 cm. Ages 4 to 5.