negative signs not displayed in ebook

Curious to know if anyone had the following problem with the ebook… For the EOC problems, negative signs are not displayed for the numbers within a table. I found this extremely frustrating after completing the problems, only to find that I have used the incorrect values. The solutions have the negative signs displayed but the original problems do not. Also, the summaries often lack the special characters within various formulas. I believe this should not be an issue after paying the substantial fees. Anyone with similar problems?