Dear Aspirant,

IISER Aptitude test is conducted every year and is one of the main channel of admission into IISERs.

The difficulty level of the examination is similar to JEE/ NEET exams and one can prepare for it whe preparing for the other competitive examinations.

For all subjects please refer to NCERT first to clear your concepts and then move on to the following reference books

For inorganic chemistry and biology focus only on NCERT.

MATH - Cengage/ Arihant publication series for concepts

Physics - H C Verma, solve every question of every chapter

Organic chemistry - Refer to  O P Tandon for questions and tricky concepts

Physical chemistry - Refer to P Bahadur

You can refer to YouTube videos for getting a better idea of concepts whenever you have doubts

If you haven't done math/biology in your class 11 / 12, it's alright. Focus on revising easy topics from NCERT before the exam.

The exam is out of 180 and if you get above 110, you should be in a really good spot to get a seat in IISER.

Hope this helps.