Developed by Dutch mathematician, Adrian Treffers, the rekenrek translates to “arithmetic rack” and is a powerful tool for supporting children to build visual models of numbers and develop numerical relationships. Rekenreks feature two rows of ten beads each, comprised of two different colored sets of five. Their structure supports children to develop one-to-one correspondence, anchor quantities to five and ten, and to develop addition and subtraction strategies such as doubles, doubles plus or minus one, making ten, and compensation.
There are many ways to use a rekenrek in a Math Talk. Listed below are two possible launching points.
The teacher and the students each have a rekenrek. The teacher composes a given quantity on her/his rekenrek, concealing the configuration from students. The teacher prompts the class: “Guess my way to make the number __.” Students compose the given number on their rekenrek. The teachers facilitates students to share their ideas with their peers.
Students usually do not have their own rekenreks to manipulate, although they could. Teacher shows a given quantity on her/his rekenrek and students show thumb up to chest when they have figured out the quantity. The teachers facilitates a discussion about how many beads the class saw and how they saw the beads.