Discover Math Matters! With over 15 million books sold worldwide, this award-winning series of easy-to-read books will help young readers ages 5-8 approach math with enthusiasm. Great for fans of MathStart or Step into Reading Math. After Jake and Leo reluctantly move into their grandfather's old house, they receive a mysterious postcard about treasure maps in the attic. Following the clues on the maps, Jake and Leo discover their new...