For some reason my brain is incapable of keeping the definitions of these straight, no matter how many times I look them up.
p → q [conditional]
q → p [converse] (con+vertere = to turn and to keep company) So the converse is "turned" or "flipped" around.
¬p → ¬q [inverse] means you negate the original conditional on both sides. From "invert" for "turned upside down." Maybe think of a cup or a bucket, flip it over it's no longer a cup or bucket. Converse... turn the cup so left is right and right is left, Inverse... flip the cup so it's not a cup
¬q → ¬p [contrapositive]