<p>My youngest son did a very similar jump in his scores. I think he might have started out even worse than you. He did not prep, he did not do self study (at least not more than an hour or two)! And I know many people disagree with his method, but it worked for him. He figured, why take a bunch of practice tests when they don’t even count? He took that dang test five times, and every single time, raised his superscore by about 100 points. So he decided that since he kept improving his score with every test, he’d just keep taking it. Not for everyone, but you get better every time you take the test, since it is such a time compressed test. Combine this with self study (or prep), and I think people can raise their score quite a bit. Of course it’s a pain to keep taking it, it costs money, but especially with the math section, people’s scores can jump around quite a bit.</p>