This is the "Mathematical Calculation Revolution" reference book from the Sundai Examination Series, published by Sundai Bunko. I've used it about 2 or 3 times, but there are no markings inside. There are no noticeable creases. It features time-saving calculation techniques and an overwhelming amount of exercises. 《Notes》 ✅ The actual product may have slight variations due to the model photos. There are absolutely no issues with the product itself, so please understand. ✅ The texture and color may appear different from the actual product depending on your device, but please understand. ✅ We will ship within 1-2 days. Shipping to Hokkaido, Okinawa, and remote islands requires an additional fee of 2000 yen. Please understand. ✅ We also accept comments, set sales, and price negotiations, so feel free to contact us! #Sundai #SundaiBunko #SundaiExamination #Mathematics #SundaiExaminationSeries