Conditional statement is a statement with a hypotesis and a conclusion:
or mathematically .
Converse statement of is statement
.
If you negate (that means stick a "not" in front of) both the hypothesis and conclusion, you get the inverse:
.
Finally, if you negate everything and flip p and q (taking the inverse of the converse) then you get the contrapositive:
.
Example:
1. Conditional statement: If I am sleeping, then I have closed eyes. (true)
2. Converse statement: If I have closed eyes, then I'm sleeping. (not necessarily true)
3. Inverse statement: If I'm not sleeping, then I haven't closed eyes. (not necessarily true)
4. Contrapositive statement: If I haven't closed eyes, then I'm not sleeping. (true)