It's a two-step process. First, a raw score is calculated. Questions answered correctly receive one point.
Omitted questions receive no points.
I math questions requiring student-produced responses. I equating section do not count toward your score. To get your raw score, a fraction of the multiple-choice questions answered wrong is subtracted from the number answered correctly. Next, your raw score is changed into a scaled score by a statistical process called equating. Your score does not depend on how well others did on the same edition you took.