Robot Games — Daily EV Drill
Pay to play a wager, or pass — 10 rounds, 6–12 seconds each, judged against the true expected value. Today's free daily session rotates a new one every day. No signup, runs entirely in your browser.
10 rounds · Play or Pass · today's session
Each round offers a wager — pay to play for a shot at a payout, or pass. You have 6–12 seconds to decide. Correct means matching the sign of the expected value, not just winning the round. Same 10 rounds for everyone today — a rotating daily set from a fixed 180-day pool.
Today's set comes from a fixed 180-day rotation — the app generates a truly new set every day.
What this drill trains
Each round poses a wager: pay a fixed cost for a shot at a payout, or pass for $0. Take a simple example — pay $3 for a coin flip that pays $10 on heads and $0 on tails. The expected value is 0.5 × $10 + 0.5 × $0 − $3 = +$2, so Play is optimal — even though there's still a 50% chance this specific flip loses your $3. That gap between "the decision was right" and "this particular round paid off" is the entire point of the drill: real market-making decisions are judged the same way, because no single trade's outcome tells you whether the decision behind it was sound.
Why this is scored by decision, not outcome
The prep guide's section on trading games describes market-making interviews as being graded on whether your spread reflects genuine uncertainty, whether you update fair value correctly as information arrives, and how you handle being picked off by a better-informed counterparty — not on whether you "won" the round. Robot Games is a compressed, solo version of exactly that judgment, stripped down to a single number: given what you knew at decision time, did you play the correct side of zero? Composure matters here too — a string of unlucky positive-EV rounds is a normal outcome, not a signal to start deviating from the math.
Related practice
- Probability & EV Practice — the typed-answer version of the same skill
- Quant interview brain teasers — worked EV and probability puzzles
- How to prepare for a quant trading interview — trading games, negative marking, and a full study plan
FAQ
What is Robot Games?
A rapid Play/Pass expected-value drill — every round offers a wager (pay $X for a shot at some payout), and you have 6–12 seconds to decide whether to play it or pass. 10 rounds per session.
How am I scored?
By whether your decision matched the sign of the round's expected value — Play is optimal whenever EV is positive, Pass is optimal whenever it's zero or negative. A positive-EV play that loses on this particular round is still the right call; a negative-EV play that happens to win is still the wrong one. That's deliberate: the drill is training the decision rule, not results-chasing.
What's a good score on this drill?
7 of 10 optimal decisions is a comfortable bar here — this is a daily habit-building tool, not a firm's actual cutoff. Net pnl is shown alongside your score for interest, but it isn't the pass/fail basis, since a single positive-EV round can still lose money.
Is this the same as a real market-making round?
No. A real trading-game interview is live, multiplayer, and adaptive, with an interviewer or counterparty reacting to your quotes in real time. This is a solo, timed EV-judgment drill that trains the same underlying instinct — does the decision match the sign of the expected value — without the social pressure or a live counterparty. It's useful preparation, not a substitute for practicing the live version with another person.
Why is the session the same for everyone?
Same reason every other test on this site is a fixed set: comparable scores, and it keeps the free web tier a step below the TradeMind app's free tier, which generates fresh sessions on demand. Web is the taste; the app is unlimited play plus firm-specific question packs and Make a Market mode.