Format and timing
Does the SAT penalize guessing?
No. The SAT has no deduction for a wrong answer. Make your best attempt on every question, and use an educated guess when you cannot solve it before the module ends.
Wrong answers do not subtract points
Leaving an item blank does not avoid a wrong-answer deduction, because there is no such deduction. That does not mean every correct answer adds the same number of scaled points: digital scoring is more complicated than that.
For a four-choice item, a random pick has a one-in-four chance of being correct. Eliminating two wrong choices raises that chance to one in two. These are probabilities for a question, not a promised fraction of questions you will get right.
Guess, mark, and return
When you cannot make progress, select the most defensible remaining choice and mark the item for review. Continue through the module, then return while time remains. You can change that answer within the active module.
Math entry questions have no four-choice shortcut. Enter a plausible numeric result if you have one, but do not burn the last minute trying random values while other solvable items remain. Practice this decision in a timed module.