Hello vasanth,
Inorder to get in ISRO, you should be done with your b.sc .
Only after b.sc you are eligible to do m.sc ,mphil in isro.
So,better complete your b.sc ,then later get in to isro
Thank you

Hello,

Well, Yes you can join ISRO but not as scientist you can join as technician or assistant engineer. But only B.Sc maths will not work it out for you to join ISRO you must need to be at least a PhD degree as you can go back to get a BE degree

So complete your Msc or directly go to complete your phd through reputed universities in aerospace research or other branches which will help you get more close to ISRO

Good Luck