In this accessible first book of algebra set in a creepy haunted house, readers will learn to find the unknown number of skeletons, ravens, and bats by using simple addition, subtraction, multiplication, and division to solve equations.In this accessible first book of algebra set in a creepy haunted house, readers will learn to find the unknown number of skeletons, ravens, and bats by using simple addition, subtraction, multiplication, and division to solve equations.