Hello,

For SSC CGL regarding Maths, RS Agarwal and Rakesh Yadav books are mostly preferred. If you need to have a strong hold on Maths, if you basic concepts aren't clear, then start with NCERT books and then proceed towards any of the above mentioned books. Also, keep your resources minimal, do not bombard yourself with too many books, you'll find it utterly confusing to deal with later on. Also, apart from these books, what matters in the case of Maths is practice, and SSC CGL repeats a lots of previous year paper, so do practice that, along with mock test and test series.

All the best!