|Other Retailer||Price Checked Time||Their Price in AUD||Our Price|
|Amazon UK||23 days ago||32.49||$13.63||You save $18.86|
|Amazon US||3 days ago||20.66||$13.63||You save $7.03|
|Book Depository US||7 days ago||15||$13.63||You save $1.37|
David A. Adler, a former math teacher, wants children to understand how much fun math can really be. He and illustrator Nancy Tobin have collaborated on two other books introducing math concepts, Fraction Fun and Shape Up! Mr. Adler is also the author of the acclaimed Picture Book Biography series for children, several Judaica titles, and numerous riddle books. He lives with his family in New York. Nancy Tobin was born in Grand Rapids, Michigan, and later studied at Kendall College. She is also the illustrator of How Tall, How Short, How Faraway, and Shape Up! She lives in New Jersey.