These quizzes are designed to help you discover, and fill, gaps in your knowledge as the course progresses. You may take or re-take any quiz as often as you like until you pass. 80% is considered passing, but I encourage you to keep trying until you can make 90%. If you pass a quiz with 80%, and later re-take it and get a lower score, you are still considered as having passed the quiz. This is supposed to be a learning tool, not a trap. You can never make matters worse by re-taking a quiz.
The first quiz is a sample, to get used to the quiz format. The remaining quizzes count toward your semester grade, and they must be passed by the date and time listed.
You should take the quizzes with no notes or textbook, and without using the Visual Basic interpreter to try out your answers. You should work alone. The point is for you to discover (and for me to discover) how much you know.
You could, of course, have a friend take the quizzes, or try to do it using the Visual Basic interpreter, or cheat in any number of other ways. But these quizzes aren't worth nearly as much as the in-class tests, and they're designed to prepare you for the tests. Besides, it doesn't make much sense to cheat on a quiz you can re-take as many times as you want until you pass.