Hello,

I hope your Board Exam Preparations are going well. Now coming to you question - I think NCERT books are sufficient enough for scoring high. Especially in maths & chemistry , most of the questions are directly asked from NCERT books.

However you can take reference from books like Xam Idea & Arihant for making your chances of scoring 90% even higher. You should practice at least 5 previous year papers & 5 solved as well as 5 unsolved sample papers. But first go through NCERT thoroughly & then only start with these reference books.

All the best.

Hope this was helpful