The *Calulus* Clever Catch makes learning how to measure fun! Metric Clever Catch® Ball provides an excellent way for children to learn and practice facts as a fun and quick game. Limits, derivatives and integrals are included. Play involves two or more players who toss the ball to each other and answer the question found on the ball under their left thumb. Directions for games and variations of play are included. 24 Inches inflated. fascinating facts make this a great playground or home activity for grades 9-12. Information on how to place your order by fax or by telephone. Product Number SR1390