Mathfinder: The Ghost in the Ruby (beginner addition/subtraction)by MindWare
Chasing a red bird through the park, you are suddenly transported to a mysterious forest. All you want to do is find your way home, but each step of your search sinks you deeper into the mystery of The Ghost in the Ruby. This intriguing story is a totally engaging new way to build arithmetic skills. The clever mystery is filled with math problems; solve the equations to work your way along the pathway that runs through the book, bringing you one step closer to solving the riddle at the end!