Hello,
Maths is not exactly necessary for b.com and i am saying this out of experience as i had taken commerce in my 11th and 12th and forgot about maths.After joining the B.com course(For the entrance exam of course i had to study maths) maths again comes back to us but it is taught as though you are a fresher.

PS:Maths is quite important for any subject especially if one is planning to enter into the finance or insurance field.
Following are the college in Mumbai:

• University of Mumbai
• H R college
• Natsee monjee college
• K J Somaiya college
• Hinduja college
• Jai Hind college
• Mithibai college
• St. Andrew's college
• SIES college
• NES ramnath college
• Thankyou