Hello Ajith

Reference books are only important if you want to practice deeper for competitions,but absolutely they will enhance your knowledge in that particular examination.

If you study your school books thoroughly and practice previous year examination papers with model papers, you will still get good marks in mathematics.

But if you have time you can solve questions from reference books in moderate to have an upper hand in the mathematics examination.

You can choose rd sharma or rs Aggarwal as both are of same level.you can get one which is available to you.

I hope it helps,

Best of luck