Logic / Unit 4 Logic 124 short lesson, about 20 seconds
The Biconditional
Captions available
The idea
p ≡ q is true when both sides match — both true or both false.
In practice
"You advance if and only if you win."
Where people slip
The biconditional is two promises: win-then-advance and advance-then-win. Most English "if"s make only one.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
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