After purchase, I flipped through the pages to check the contents, but I haven't written anything in it. I don't see any noticeable stains, but there's a possibility I missed something. Please understand that this item has been stored at home, inspected by a non-professional, and is a used item. "7 Secret Tools for Math That Elementary School Students Can Solve in 5 Seconds" by Akito Ton Price: ¥1100 #Akitonton #Book #Nature/Mathematics