This is a reference book that provides a detailed explanation of basic problems in Mathematics I and A. - Title: Mathematics I & A Basic Problem Mastery - ISBN: 978-4-00-034198-2 - Author: Kenji Ueno Price: 1320 yen Some parts of the answers have been highlighted with a highlighter, but most of the writing on the problem statements and diagrams has been erased. I think it should be fine for solving the problems. Thank you for looking.