Hello Aspirant!
As you have not mentioned the name of institute you are seeking admission in, I'm answering to your query w.r.t. DU admission guidelines.
If you are a PCMB student, for admission in B.Sc. (Hons.) Computer Science, you must have passed in Mathematics with 60% or more marks. It means Mathematics is compulsory.
And it is even mandatory to include marks obtained in Mathematics at (10+2) level while calculating your 'Best of Four' aggregate.

So, if you are a PCB student, you won't be eligible to apply for B.Sc. in Computer Science in DU.

Infact in most of the other institutions, atleast qualifying Mathematics at senior secondary level would be needed. And even if you get a chance to do B.Sc. in C.S. in any institute without having a Mathematical background at (10+2) level, which is a rare possibility, you may face difficulties during your graduation.

Don't hesitate to ask if you have any more queries.
Hope this answer helps.

Hello aspirant,

If you took subjects PCMB then you can have a chance to apply for Btech in CSE. But if you didn't take Maths in you 12th then you cannot apply for Btech because to get admission for CSE a candidate must have 10+2 with Mathematics and Physics as compulsory subjects.

Thank you