I'm trying to print exams. I would like each exam copy to have it's own number on it (the first copy has 1 on every page, the second copy has 2 on every page, etc.,) Can someone explain to me how I can do this?

It can be achieved using a script, like this one I've developed: Custom-made Adobe Scripts: Acrobat -- Create Copies with Unique Codes

Here are a few ways;

1- If you would be happy with the exam number on the first page only, you could use Bates numbering (Tools> Organize> More> Bates numbering> Add) you will first need to duplicate the PDF for each version needed and drop them into a folder.

2- Duplicate the PDF, rename each one to the exam number, e.g Exam 001, Exam 002, etc. then include the file name when printing.

3- Pre-print the paper with the exam numbers, e.g. if the exam is 8 pages long and you need 40 copies, make a 40 page PDF with only the exam numbers included (001-0040), then print 8 copies of the numbers (stacked, not collated). Return the paper to the printer and print 40 copies of the exam (collated, not stacked).

4- You could also use data merge from InDesign.