Yotsu-ya Otsuka Pre-Study Series Science, 6th Grade Exercise Workbook: Volume 1, Answer Key 1 (some answer sheets missing) Volume 2, Answer Key 1 (some answer sheets missing) Total: 4 books. Names will be erased or cut out before shipping. Workbooks: Generally no writing, but there are occasional red pen check marks for incorrect answers. Answer Keys: Some answer sheets are missing as they were submitted for homework. These books were used at a cram school, so they are offered to those who don't mind minor imperfections. For students who will finish in 2026.