Sayan,  

NCERT book for maths has good explanations and standard problems and if you are very good and sharp at solving problems, you may not need to do more problems from other books. But I would personally suggest you NOT TO RELY ON NCERT ONLY.  In 2016, when I took the paper,  I guess there were some different questions too which were not in NCERT. You should practice questions thoroughly from refresher books like RD SHARMA. RD SHARMA, I would say is enough for scoring above 90 in mathematics. You should go through each and every solved example given in the book and practice exercise problems as well. NCERT problems are directly asked in many exams, so don't miss any of them. 

Hope this helped! 

All the very best for your exams.