Books 1-3 in the bestselling Math Inspectors series for kids! NOTE: This paperback edition collects books 1-3 in a single 400 page volume and is NOT a boxed set. Stanley, Charlotte, Gertie and Felix are just your typical twelve-year old kids. They love to hangout after school, they love burgers and milkshake, and they love math. Wait. What? And if there's one thing they love even more than math, it's solving mysteries....