Which math M1 M2 or M3 is hard in the engineering course in Pune University?

Ony of my sisters is a part of Pune University and as per what she mentions, it is best that you practice the fundamental mathematical problems. Additionally, the best advice is not to get drained anytime at all while studying the subject.

Now, when shifting focus to your question, 

• M1 incorporates basic algebra and is deemed pretty simpler than usual. 
• On the other hand, M2 might still be difficult, yet it can however be aced if you practice the basics of integration and derivation.
• In the case of M3, the course entirely depends upon the fundamentals you have earlier prepared for M2. 
• After a brief elaboration, it is best that you rather choose preparing for M2, because it can contribute to making the subject quite easier. 

The study standpoint is curated as per the syllabus, and is best if you follow the pattern in accordance with it.