When you multiply two integers with different signs, the result is always negative. Just multiply the absolute values and make the answer negative. When you divide two integers with the same sign, the result is always positive. Just divide the absolute values and make the answer positive.
Your volume would be 27 inches cubed. This is because Volume = length x width x height. If you multiply 3 x 3 x 3 you get 27. This resulting in your answer being 27.