My Book of Subtraction, Ages 6-8, Revised Filled with activities, full-color images, and the trusted Kumon learning method, students will learn to add single-digit numbers in a step-by-step manner, which enables them to gain solid calculation skills without being confused about decimal places. With just the right amount of practice, kids can master each topic and gain confidence without becoming bored or frustrated. Building basic subtraction skills is vital to understanding the decimal system, the foundation of higher-level arithmetic concepts and skills taught in school curriculums. Paperback, 80 pages. Recommended for ages 6 to 8 years old. Grades 2-3