Hello,
Yes, you can do so. The eligibility criteria for BEd is graduation with at least 50% marks. You have to give an entrance exam for the admission, and yes, you should give the subject of your choice to write the exam. In this way you can do the BEd through Arts. B. Ed. in mathematics can be opted by any student who has taken mathematics as a main subject in his or her graduation. This course can be done by B.Sc maths or B.A math students. Then don't be upset if you want to choose a different subject than your graduation you can take it in B. ED but the only condition is that then you have to do a post-graduation degree in the Subject you want to choose.
BEd Course can be done in various specializations. Each specialization focuses on the subject chosen by the student. students who favor Commerce should prefer BEd Commerce Syllabus and students who like computer science may opt for BEd Computer science syllabus.
BA with history, geography, economics or political science gives better advantage as Social science teacher. Other also have the subject requirement to become teacher.
The minimum qualification required for entry into B. Ed. course is intermediate (10+2). While students from the Arts stream are trained to teach subjects like History, Civics, Geography, and languages, the students from the Science stream are trained to teach Mathematics, Physics, Chemistry, and Biology.