Help, Adding & Subtracting of measurements?

Hi, I'm taking a Math entrance exam to get into a 4 year college. Some of the arthematic is giving me problems, for instance, adding and subtraction units of measurments:
subtract 9 feet 5 inches from 6 feet 6 inches = (?) or add 10 feet 4 inches and + 8 feet 3 inches = (?)