1. A logical statement formed by negating both the hypothesis and conclusion of a conditional statement and reversing their order; if the original statement is 'if P then Q,' the contrapositive is 'if not Q then not P.'
Usage: logic; mathematics; plural form of contrapositive

Examples

• In logic class, we learned that a conditional statement and its contrapositive are logically equivalent.
• The contrapositive of 'if it rains, then the ground is wet' is 'if the ground is not wet, then it did not rain.'
• Students often confuse contrapositives with converses, but they are not the same thing.
• To prove a statement true, mathematicians sometimes prove its contrapositive instead.
• The contrapositives of several related theorems were examined in the geometry unit.