"The Arithmechicks are headed to the beach! Their good friend Mouse is going to compete in a sandcastle contest. The chicks are excited to play all sorts of beach games--including volleyball and surfing--as they cheer on Mouse. Readers are invited to add and subtract as these math-loving chicks also explore fact families--and to watch as Mouse, along with their new friend Crab, create a magnificent sandcastle! Will they win a prize? This book includes...