The Math section of the SAT is not weighted more heavily than the English sections when calculating your overall score. This means that you can have a lower score on the Math section and still make up for it with higher scores on the Reading and Writing sections.
For example, if you get a score of 200 on the Math section and 750 on each of the English sections, your total SAT score will be 1700. This is a good score, even though your Math score is low.
Of course, it is still important to try your best on all sections of the SAT, including the Math section. But if you do happen to do poorly on one section, don't panic. You can still get a good overall score if you do well on the other sections.