Kumon Math Boosters: Addition & Subtraction, Grades 1-3, Ages 6-8, 144 pages by Kumon Publishing

The Kumon Math Boosters series is designed to help children who either need to improve their basic math skills, or who are slightly ahead of the curve. They accomplish this by combining multiple years of curriculum in one book and following the famous step-by-step Kumon approach, which reduces anxiety and frustration. Whether your child needs a little extra review and reinforcement or is ready to jump ahead to the next level, Kumon Math Boosters are the right choice.