I am currently writing a math textbook for a class. Considering my book is geared towards the class, I want it to match the course's curriculum. However, the curriculum for the class is centered around its required textbook. Although the words in my textbook are entirely mine, the organization and also the content I choose to teach is mostly similar (only a fraction of the topics are covered). Obviously, I don't want to get into any trouble like plagiarism, and I was wondering what your guys thoughts were.