2010 - Pythagoras and the Ratios a Math Adventure (Hardcover) → Paperback ISBN-13: 9781570917752 ISBN-10: 1570917752 Genre: Children's Books ? 2010 - Pythagoras and the Ratios a Math Adventure (Paperback) → Hardcover ISBN-13: 9781570917769 ISBN-10: 1570917760 Genre: Children's Books ? |