Use the full terminology for all of the math functions and procedures you are teaching. You don't need to shorten any words or leave anything out like you might when teaching younger students.
Put examples and illustrations into adult terminology by using everyday examples that relate to an adult's life. Things like buying gasoline, paying the electric bill and balancing a checkbook are all adult situations that relate to math and will help adults get a better understanding of the math concept you're teaching.
Use slang and other adult terminology to make sure you are speaking on an adult level. If you don't use the same slang and wording they use, you might make them feel as if you are talking down to them or trying to go above their heads. This is especially important in math classes, where unfamiliar terminology and concepts can make learning more challenging.