What is "cuisenaire rods"

n. (plural of Cuisenaire rod English)

Cuisenaire rods are mathematics learning aids for students that provide a hands-on elementary school way to explore mathematics and learn mathematical concepts, such as the four basic arithmetical operations, working with fractions and finding divisors. In the early 1950s, Caleb Gattegno popularised this set of coloured number rods created by the Belgian primary school teacher Georges Cuisenaire (1891–1975), who called the rods réglettes.