is this possible commerce student can do BCA after 12 without taken maths in 12 class
Ofcourse,yes. if you're asking that you didn't have maths in your 10+2 but want to get into BCA. But in place of that, you'll need to have Computer Science/Statistics/Computer Applications. And there will be mathematics in at least 4 out of 6 semesters in BCA, so you might need to attend your classes well to keep up a decent score.