Was ncert books was useful for preparing for jee mains?

Yes, NCERT books are very helpful for JEE Main preparation as syllabus is based on them.

To score good marks in JEE Main it is very important that your concepts should be clear. So, that you can easily solve tricky questions.

You can recommended other books as well for your preparation but make sure you read NCERT books throughly.

To boost your preparation level it is important to refer previous year papers and complete mock test series for your practice. Make sure you do analyse every mock test series. So, that you can learn from your mistakes.

All the best!!