Cuisenaire Rods are versatile mathematical tools used in elementary schools as well as in other educational levels and even with adults. These rods are used to teach a variety of mathematical topics, including the four basic arithmetic operations, fractions, area and volume calculations, square roots, solving simple equations, systems of equations, and even quadratic equations. The rods, originally called "réglettes" in French, are named after their inventor Georges Cuisenaire, a Belgian elementary school teacher who published a book on their use in 1952. The application of the rods in both mathematics and language instruction was developed and popularized by Caleb Gattegno in many countries around the world.