Yes, you can get admission in DU with maths as an additional subject.
Also, for your information, maths isn’t a compulsory subject for many courses in DUvarying from course to course and college to college.Many undergraduate courses in DUdon’t require maths as a prerequisite subject.
• BA(H) History, BA(H) Philosophy, BA(H) Sanskrit, BA(H)Urdu, etc.
• BSc(H) Zoology, BSc(H) Anthropology, BSc(H)Botany, etc.
For any other questions, write back.
If you want details on the admission process, check Admission In University of Delhi ( DU ).