how difficult is btech math? i'm allowed to have a transfer credit cuz i got an 8 in 1ZA3 math and am allowed to transfer that credit so i don't have to take math for the entire year. I need a high CA and i'm not sure if i should take the transfer credit or take the course during the year? any advice?

It wont be harder than 1ZA3. If I were you, I'd probably look into taking an easy course to bump your average up, since you got a free time slot.

If you got an 8 in 1za3 you will be fine in btech math...but first term btech math deals mainly with integration and linear algebra(1zb3&1zc3), so if you took these 2 courses, then you should be fine for the first term math!
I think 2nd term btech math is like all differential equations..

not too hard

Not sure about difficulty but if I recall my friend in btech he learned stuff faster than eng math. Learned more but not as thorough