If I am not required to fit my answer in the space provided - I can put my answer on another sheet to avoid needing to erase. I have two reasons for this. I think that one of the main reasons I take a test is to help me know if I actually know the material. Secondly, I want to make sure the instructor did not make a mistake on my test. It does happens.
Teachers are only human, and sometimes they have so much to do that they make a mistake.
Don't gloat about it if it happens. Just be nice and explain your thoughts. Go back to the WebQuest now and continue working on making a test-taking plan.