Kumon Easy Telling Time: Write and Wipe! (Kumon Flash Cards)

I was carried away with the initial set of Kumon books that I purchased. My son loved his first set of books - mazes (finished the whole book in less than a months time), coloring book and jigsaw puzzle book. Since he is so interested in all things mechanical including clocks, I thought this would be a constructive one and help him to learn to tell the time. But there is nothing special about this book and I dont see why it claims to be teaching time the kumon way... It has write and wipe cards for each hour, half hour and quarter. That is all.