A fair six-sided die is rolled and you're paid $X equal to the face value. What's the fair price to play this game once?

How to answer

Fair value = expected payout = (1+2+3+4+5+6)/6 = 21/6 = $3.50. You'd pay up to $3.50 to play; the game has zero EV at exactly $3.50. This is the base case for every fair-value question — fair price equals expectation.

Key idea: Average the faces.