Two fourth-grade calculation workbooks, sold together. The answers are in the back of the book, not a separate booklet. Upon inspection, I found markings on two pages. See photos 8 and 9. Other than that, there are signs of use such as page openings and corner folds, but there appears to be no other writing. Please forgive any oversights. No individual sales. Would these be suitable for home study? For those who understand that these are used items, thank you.