Your Kumon center director has the official solution book. Most instructors are willing to photocopy a specific solution for a problem you are stuck on. If you bring in your work, they will show you the error using their solution guide. This is the safest and most effective method.
To prove why you need a quality solution book, let’s compare a poor answer versus a top-tier answer for a typical Level L differentiation problem: kumon math level l solution book pdf top
Problem: Differentiate y = e^(2x) * sin(3x) Your Kumon center director has the official solution book
A: Kumon’s philosophy is "self-learning through struggle." If students see the solution immediately, they skip the cognitive struggle that builds long-term memory. The solution book is meant to be a last resort for the instructor. Purchase or request materials from Kumon