If you wish to go for the BSc Hons. in Computer Science, then you need to have Mathematics in your 10+2. Without Mathematics you aren't eligible for the BSc Hons in Computer Science for most of the universities/colleges. If you wish to go for Computer related course, without Mathematics in your 10+2, then you can go for the BCA course. There are many BCA colleges in India which offers the BCA course without having Mathematics in 10+2.  The curriculum of BCA and BSc CS is different, but if you are wiling to join private IT companies, then BCA can provide you the same opportunities as that of BSc CS.

For more information BSc in CS consider the link below:

https://www.careers360.com/courses/b-sc-computer-science

For more information regarding BCA consider the link below:

https://www.careers360.com/courses/bca-bachelor-of-computer-applications

I hope this helps. Wish you a great day!