Racecourse cardsharps used this counting game to fleece strangers
Two players take turns turning over a card (values 1-6) and adding it to a running total, calling out the new sum. Whoever first makes the total exactly 31 wins. Would you rather go first or second — and what's your winning plan?
Reveal the answer
Go first and lead with a 5. Then steer the score onto the ladder 10, 17, 24, 31 by always bringing the total to one of those numbers yourself — mirror any 5 your opponent plays with a 2, and you can't be stopped. Dudeney called this a classic racecourse hustle dressed up as fair play.
— Henry Dudeney, The Canterbury Puzzles — Puzzle 79, 1907
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