Some people just prefer doing exercises in good old paper sheets, so we have made every exercise from the site also available in PDF.
You can generate, save, print, hand-out or do anything with these files with no authorization required. But please mind the environment and only print pages you really have to. Darfyx will always be here for you to practice online.
And just recently we have added answer keys at the end of the files, which will make your life easier if you are studying on your own. Enjoy!