Hello Chandan. I hope you are doing well and your health is good. You mentioned your percentage in 12th board exam but didn't mention the category where you belong to. So, I assume you are from General category and I will give an answer on the basis of that assumption. Well, based on your performance in 10+2 board exam, you have good opportunity to grab a seat for B.Sc. (Hons) in Mathematics at the following branches that comes under DU:

1. Shri Guru Tegh Bahadur Khalsa College (Expected Cutoff in 2021 - 95-97.00%)
2. Hansraj College (Expected Cutoff in 2021 - 95-97.75 %)

Please note, Delhi University cutoff marks will be prescribed on the basis of marks obtained in the best of four subjects of the candidates in12th board exams or any equivalent qualifying exam.

If you want to know more about cutoff trends in DU then refer to this article: https://university.careers360.com/articles/du-cutoff

I hope you find this information helpful.

I wish you all the best for your success.

Thank you and good luck!