The Mysterious City of El Numero

Daisy and Dale's father, adventurer Darren Deed, has
gone missing during a mission to South America. After the kids receive a
mysterious package in the mail, clues unravel that might lead to his
whereabouts?possibly the mysterious city of El Numero. Daisy and Dale need
readers' help, and math skills, as they attempt to rescue their father. This
clever volume seamlessly combines an exciting adventure story with need-to-know
math concepts and is packed with appealing illustrations. After solving problems
in this fantasy world, readers will find themselves making more math connections
in their own lives.