The Textbook code comes with the DVD-rom, and lets you unlock your textbook online. The optional Classroom code comes from your teacher. You use this code to join your teacher's classroom, where you can see your classmates. The Exercise Completion code is the number you get at the end of each exercise. You write it in your homework book like usual. Only the textbook code is needed to start your Online Homework.
**What if your DVD-rom doesn't come with a Textbook Code?** Email email@example.com with the following information: