Each proofreading exercise contains only a handful of errors.
Most proofreading exercises are crammed with spelling mistakes and grammatical slip-ups. Every other line features a glaring faux pas of one sort or another.
In the real world, you’ll be proofreading copy that is likely to have been produced by professionals, by people who take the quality of their output very seriously. They actually don’t want to have their inadequacies pointed out to them, so they’ll be doing their level best to create error-free documents.
The proofreading exercises on this website, like The No-Nonsense Proofreading Course itself, will prepare you to actively pursue and carry out genuine proofreading assignments. In the real world. Not in some bizarre parallel universe where documents are created by bumbling individuals incapable of stringing a sentence together.
Good luck with the exercises!