Description Week 1 - Addition 2, 3, 4 Week 2 - Addition 9, 8 Week 3 - Addition 7, 6 Week 4 - Challenge! Calculation Champion Week 5 - Addition 5 Week 6 - Challenge! Calculation Champion Math Starts with Understanding the Principles Math is an abstract subject that expresses the relationships between concrete objects through numbers and symbols. This is the main reason children find math difficult. Math can only show its true power when it's backed by genuine understanding. At every stage, understanding the underlying principles is what matters most. A Shift in Math Education The era of math education where simply knowing how to get the answer was enough is coming to an end. Rather than repeating a single method over and over, it's important for children to learn a variety of problem-solving approaches even in basic calculation. Textbooks teach why things work the way they do and encourage multiple ways of thinking, but students often fall into mechanical repetition, forgetting the underlying principles and losing the ability to apply what they've learned. Consistent practice in calculation is organized into 4 to 6 books according to each stage of preschool and elementary learning, designed for just 10 minutes of study a day. Learning principles and various methods is made fun through illustrations, practice is varied, and each unit wraps up with focused review. With this manageable daily amount of study, children will find their calculation skills steadily and noticeably improving over time. The revised edition of Wolli Sem includes expanded video lectures and strengthened principle-based learning for upper elementary grades, making it even easier to understand principles, concepts, and calculation methods, while reinforcing practice for a more complete learning experience. We hope Wolli Sem can be the answer to parents' concerns about how best to help their children learn math.