This is a book on numerical reasoning! I've been all over the place with books on numerical reasoning, using things like the Tamatebako and Wani-bon, but this one was the easiest to understand! I used it a lot, so the cover has some wear and tear. There's also some writing in the first half of the book, but the second half is clean, and the writing is in pencil so it can be erased! I don't think the year matters too much! Kangaroo Book Civil Servant Exam Numerical Reasoning / Numerical Processing