Desk · take or pass Streak 0 · best 0
Their market
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bid / ask · you buy at the ask, sell at the bid
Buy at ask Sell at bid Pass Next contract
Work out the fair value before you click.
Every contract settles for real after you decide. Expected edge measures the quality of your decision; realised P&L adds luck. Over many trades the two converge.
Briefing · Trading floor Card Game Skill: EV, edge detection Firm echo: SIG
Someone quotes you a two-way price on a random quantity. You may buy at their ask , sell at their bid , or pass. Your only job is to compute fair value fast and compare.
Fair value above the ask → buy. Edge = fair − ask. Fair value below the bid → sell. Edge = bid − fair. Fair value inside the quote → pass. Trading there loses money on average. Shorthand
Max of two dice = 161/36 ≈ 4.47. Min = 91/36 ≈ 2.53. They sum to 7.Waiting time for probability p → 1/p. Rolls until a 6 = 6.Product of independents → multiply EVs. Two dice: 3.5² = 12.25.E[X²] = Var + EV². One die squared: 35/12 + 12.25 = 15.17. Reopen any time with How to play . Deal me in