Giant Magnetic Number BondsEasily demonstrate number relationships on the whiteboard! colorful, magnetic circles, squares, and counters are designed to demonstrate fact family and part part whole relationships for the entire class. Great way to build addition and subtraction skills. This comprehensive set includes 3 Circle and 3 square number bonds (8" and 9 1 2" in diameter, respectively), 4 connecting lines, and 45 magnetic counters measuring 1 1 4" each. Recommended age 5+