For more than 50 years Cuisenaire Rods have been helping children visualize essential math concepts from the very basics like counting to learning addition and subtraction, multiplication and division, fractions and decimals, measurement and equivalencies even basic algebra. This Intro set contains 10 different sizes and colours and each colour represents a different rod length that can be assigned a different numeric value or unit of measure. Set includes rods, convenient storage trays with lid and a Teacher's Guide. Longest Rod measures 10cm, suitable for 4+. Interlocking rods also available.