Looks like the official digital version is only on Kindle Japan (need a Japanese Amazon account) or Rakuten Kobo . The free PDFs floating around are all missing the answer key pages. Just buy the book, folks. It's worth the $20.
Teaches you to follow the flow of an argument, identify cause-and-effect relationships, and track pronouns (like kore , sore , are ). Shin Kanzen Master N3 Reading Pdf Download