Dear Amrutha, thankyou so much for letting us serve you with an answer. 

Proper mathematics is not included in the BBA or MBA curriculum but there are particular subjects which deal with calculations such as Business statistics ,Business accountancy and Cost accountancy. You will not find it difficult to deal with these subjects if you were a commerce student but other stream students have to get to the basics and understand new concepts which is not impossible to do but it takes a little efforts. Also, most of the institutions allow the use of calculator as the calculations are really complex and time taking so, it will not be a problem. 

Thankyou.