Converse: Q => P
The converse of P=>Q is Q=>P
The Premise(P) and the Conclusion(Q) switch places. The Conclusion becomes the Premise, the Premise becomes the Conclusion.
Inverse: not P => not Q
The inverse of P=>Q is (not P => not Q)
Negate both the Premise(P) and the Conclusion(Q)
Contrapositive: not Q => not P
The Contrapositive of P=>Q is (not Q => not P)
Contrapositive a combination of the converse and the inverse. To get the Contrapositive just Negate and switch The Premise(P) and The Conclusion(Q).
P = The Traffic Light is Green
Q = The Car Drives over the crossing
P => Q is then:
If the I fall into the lake, then I get wet.
The Contratpositive of P => Q is then: not Q => not P is then:
If I am not wet, then I did not fall into the lake.