Hello dear

NCERT is the best and most crucial books for the 12 th preparation ( if you are only concerning about the boards exams. I would suggest you to go with concepts and theory of each topic . And in some of the topics or specialy in physics you can go with some other book like HC. VERMA here you will get a good quality questions for practice . Maths book has enough questions for practice and chemistry book is also good and contain all the necessary topics and questions but if you want to know more about the theory and other good quality questions for practicing of subject you can solve other books also but first go throt the NCERT

And if you are preparing for some entrance exam than you should go with other books also like Arihant , dc Pandey, op tondon, rs Sharma , rc Mukherjee etc. Because you would require a good practice to crack the exam.

GOOD LUCK

Hey Maanik,

Hope you are doing well!

Well dear,NCERT book is sufficient for Chemistry,but,not sufficient for maths and physics as you need alot of practise in these subjects.

So,do refer to a reference book along with NCERT.

Hope This was helpful!

All The Best!

Keep Smiling :)