They do not teach you the basics, you need to study yourself. It all depends on what you mean "I'm not a good in...", it's relative. Well, it's not nucleonics, but you can struggle, it can take longer to get axams done or even fail to pass the exams if you forgot basics of math and physics.
Try to register in any of free sample ATPL question banks and go through it. Especially through subjects like General Navigation, Mass&Balance, Aircraft Performance and maybe Meteorology for physics... That's the level of math and physics needed. You will soon find out, whether it's for you or not.