Get better and faster In our fast-paced world, precision and speed are valuable qualities. Kumon Speed and Accuracy Math Workbooks give your child the competitive edge they need for school and beyond. On each page, children time their progress, so they can see their skills and speed improve. If your child can subtract numbers 1 through 20, then this book will increase his or her speed and accuracy when subtracting. Use this book to help your child practice and master basic subtraction.