Teachers know that managing a class is no small task. They have to manage grades, rosters, and at times, even seating arrangements. LearnBoost is a website that tries to merge all these features into an online interface, with a focus on grading. If you are a teacher, all you need to do is create an account on the site and then set up your school.
If you want to edit every aspect of a PDF, including the content and the layout, you're going to need a professional tool like Adobe Acrobat. If all you want to do is split one PDF into two, or combine two PDF's into one, I Love PDF can do the job for you.