iv drips have to be rounded to whole numbers because drops of fluid cannot be cleaved into partial drops--there are whole drops and that is it. when you actually see an iv in action you'll understand.
the same applies to teaspoons and mls of things like syrups when you are using medicine cups in pouring them out. an exception would be if they are being measured out with syringes where they can be measured as accurately as to 1/10th of a ml (or cc). again, when you actually see one of the medicine cups or syringes you understand immediately why the math problem would be rounded to that specific kind of answer.
otherwise, follow the rounding principles.
when it comes to your individual instructors, ask each before a test what they will accept, or want, before turning your final answers in to each of them, so you minimize your chance of goofing up on the rounding. or, show all the answers, unrounded and rounded, so you can argue later for the points if an answer gets marked wrong.