This is a set of English and Japanese problem books and answer keys from the Spurt 10 series. I purchased these in 2019 and they have been stored away, so I am now selling them. I haven't found any writing in them, but please note the following: ↳ There is a crease on the back cover of the problem book (photo 3). ↳ There is some wrinkling on the bottom of the back cover of the answer key from when I erased my name (photo 5). These are educational materials for cram schools, so they are likely difficult to purchase in bookstores. - Language: English - Language: Japanese - Publisher: Tokkyocho Kyoiku (Patent Office Education) - Series Name: Spurt 10 Please consider purchasing only if you understand that these are pre-owned items stored by a private individual.