Guess the Edge
A bet combination appears. Estimate the house edge. The Bet Builder arithmetic then reveals it, line by line.
Six rounds from a pool of fourteen. European, American, French and mini tables; single bets and spreads. Within 0.1% scores 3 points, within 0.5% scores 2, within 1% scores 1.
Round 1 of 6
Scoring
16–18: you do the arithmetic in your head.
11–15: you know the four numbers (2.70, 5.26, 1.35, 7.89) and when they blend.
6–10: you know the European edge; the other tables are on the Variations pages.
Under 6: read House EdgemathHouse edgeThe share of each stake the casino keeps on average: 2.70% in European roulette.Read full →, then Bet Builder. The rule is one line: edge = −Σ(stake × EV) / Σ stake.
How the reveal works
Each component bet has its own expected valuemathExpected valueThe average result per bet over the long run. −1/37 of the stake for every standard European bet.Read full → per dollar: (payoutmoneyPayoutWhat a winning bet returns, quoted as “X to 1” on top of the returned stake.Read full → base − pocketsequipmentPocketOne of the 37 numbered compartments on the rotor. Also: slot, cup.Read full →) / pockets, which is −1/37 on a European table, −2/38 on an American one, −1/13 on mini roulette, and −0.5/37 for even-money betsbetEven-money betRed/black, odd/even, high/low. 18 numbers, pays 1:1.Read full → under la partageruleLa partageFrench rule: when zero hits, half of an even-money stake is returned. Halves the house edge on those bets to 1.35%.Read full →. The American top line is the exception, paying 6 to 1 on five numbers for −3/38. Multiply each by its stake, add, divide by the total stake. The Bet Builder tool does this for any spread you like.
Questions
Because every standard European bet is −1/37 of its stake, and a sum of such bets is −1/37 of the total.
The French blends. Even-money chipsmoneyChipA token representing a fixed amount, placed on the layout to make a bet. Also: check.Read full → are at 1.35% and everything else at 2.70%, so the answer sits in between, weighted by stake.
Comic relief
Guess, then see the arithmetic.
Sources
- Ethier, S. N. The Doctrine of Chances: Probabilistic Aspects of Gambling.