Quant Trading Interview Math: Expected Value, Probability Puzzles & Market Making
Price dice and card games, solve Bayes puzzles with tables, find stopping times, size bets with Kelly, value options on dice and coins, make a market with inventory P&L, structure Fermi estimates and drill mental math: 8 graded labs.
The first lesson is free — no account needed.
About this course
Quant trading interview practice for candidates who want the probability and expected value questions to feel routine, built as eight labs that check every step. You price a die roll, a die with an optional reroll and a card draw by expected value, solve coin and card puzzles with Bayes tables, read the geometric distribution and the expected wait for two sixes in a row, size a 2-to-1 bet with the Kelly criterion and see why twice Kelly earns almost nothing, price calls and puts on dice and a two-flip coin tree and check put-call parity, make a two-sided market and track inventory, cash and marked-to-market P&L, structure a Fermi estimate with low, base and high cases and drill mental math with formulas. The questions are in the style of trading interviews, not from any firm. Educational only, not investment advice. The first lab is free.
Lessons
- Expected Value of Games: a Die, a Reroll Option and a Card DrawFree
- Conditional Probability Puzzles: Bayes Tables for Coins and Cards Pro
- Expected Stopping Times: the Geometric Distribution and Two Wins in a Row Pro
- Variance and Kelly Sizing: How Much to Bet on an Edge Pro
- Fair Value of Option Payoffs on Dice and Coins: Calls, Puts and Parity Pro
- Market Making: Quoting a Spread, Tracking Inventory and Marking the P&L Pro
- Estimation Questions (Fermi): Break It Down, Bound It, Round It Pro
- Mental-Math Drills Checked by Formulas: Percentages, Compounding and a P&L Chart Pro