236 is pretty required for all EE graduate.. however there are lots of past exams and assignemnet... just get it from 學長學姊 they change questions every year but it's alwasy in same sytle so shouldn't be too much trouble
212 .. was told not easy and lots of homework... if just wanna fullfill the math requirement.... suggest Graph Theory 1 & 2... it's not too much work and you will actually learn stuff... so be much better learning experience.
345... i have completely no idea.... and i think the ones who took it were actually my 學長 so might be a while ago...