It’s in addition. I’m years removed from college but I read about it recently because a few people were bringing it up. It’s basically assigned homework that a teacher can choose to utilize instead of doing the work themselves. So let’s say you pay $200 for your textbook. If your teacher wants to use the homework assignments provided by the publisher, each student would have to pay an additional $50 to access that “feature”.’ So in essence you are paying for the right to do homework. (In some cases it’s more than $50. That number was arbitrary)