expression problem

Hello guys, has anyone encountered problems with expression function in latest version, like when you trying to add rad(angle) in to rotation and it doesnt work? For that I can just use radians, but how to deal with expression like int(number) extract integer part of certain number? I remember david once showed us how to do that in online seminar by using expression.  I tried servral times and it does not work. Full name or short name. Can anyone help me? Thanks