Hi, you can sit for Maths exam through NIOS. The eligibility criteria for getting into an engineering college would be 50% aggregate in PCM. For studying abroad you will have to appear for English proficiency test. For colleges in India SAT score is not required as many of the colleges do not consider it. You will have to appear for entrance exams such as state level CET or JEE Mains. Either way once you appear for maths you will be eligible for both in India as well as for abroad. Hope this helps.