hand2mind offers a wonderful selection of Rekenrek arithmetic tools and resources for math. Rekenreks - also known as arithmetic racks or calculating frames - are ideal for building number sense in younger children. The Rekenrek manipulative system provides students with a concrete, physical object to help develop and deepen their understanding of numbers. Children build a strong sense of 5 and 10, learning about the relationships among numbers and gaining confidence in counting and other simple math operations along the way. See the complete line of Rekenrek individual student frames, classroom demonstration sets, teacher guides, virtual manipulatives, answer boards and much more.