What do those numbers mean? What's the maximum?
The maximum points allowed on the SAT is 800. Every question you get wrong, however, deducts points, versus not counting at all.
That's not exactly correct. For multiple-choice questions, correct answers increase your raw score by 1 point. Where n is the number of options, wrong answers deduct 1/(n-1) points. That way, random guesses average out to being a waste of time.
The correlation between raw score and final score (the 0-800 scale) varies from test to test, according to the following parameters: If you get everything wrong, you get a zero. If you get everything right, you get 800. If your raw score is zero, you get 200. If you get the average raw score, you get 400.
Because of the scaling, you can usually get 800 even if you answer one or two questions wrong. I scored 710 in math for getting one question wrong. One no-answer was worth 800. Because of the way it's scaled, 1/4 raw point made a 90 point difference on my particular test. There were other people that took the test the same year as I did (different variation), and scored 740 for getting 3 questions wrong, which just goes to show how awesome standardized tests are.
The first lesson in the SAT prep course I took included a graph of the correlation between family income and SAT scores. Can you guess what it looked like? I'll give you a hint: rich families can afford better prep courses.
If you see a word you don't recognize, just skip it. There are plenty of other questions that are worth just as many point. If you've got time when you're finished with the section, go back. Also, guessing, as long as you have at least some intuition about the right answer, is always worth it, because unless your intuition sucks, it's going to throw your raw score higher on average, not lower, since randomly guessing has no effect on raw score.