Learn the Math Behind Betting Markets
Ten short lessons, five classmates, no paywall. No account, no email, no card.
Where to start
None of this is a pick. Every number on the site is arithmetic on something you typed or something a venue posted.
Meet your classmates
They turn up in every lesson below. Only the situation changes.
- Average JoeBets on whatever is in front of him, immediately.
- Bookie BrianRuns the board. Writes the prices. Never guesses who wins.
- +EV EvanWaits. Only bets when the number is wrong.
- ChalkA hamster. Wins half the time.
- PipA hamster. Also wins half the time. Everyone likes him more.
Your rank
Pass all ten quizzes to climb from New Kid to Teacher, wearing your rank as flair in the Discord, with your first month of Extra Credit free at the top.
- New Kid
- Line Leader
- Front Row
- Gold Star
- Sharp Pencil
- Bookworm
- Hall Monitor
- Curve Setter
- Star Pupil
- Teacherfree month
Teacher. All ten, all correct. Take the desk.
Your first month of Extra Credit is free. Claim it on the pricing page: the button appears there once you are signed in, because the ten passes are checked against your account rather than taken on trust.
It is the ordinary subscription with the first month at zero, so Stripe asks for a card, it is one per account, and cancelling is one click in your account menu. After the free month it renews at $39 unless you cancel. Saying that here rather than only at the checkout is the point.
Extended reading
The deeper shelves. None of it is on the rank ladder; all of it is free.
More on prediction markets
A sportsbook hides its cut inside the price. A prediction market charges you a fee instead, and posts the price as a straight probability. Lesson 10 covers the basics; these three go deeper, and none of them is on the rank ladder: the ten above are the whole climb. The Kalshi taker fee is per contract. It peaks at 1.75¢ on a coin flip and gets cheaper toward the edges, which is exactly backwards from sportsbook vig. Vig is heaviest on longshots.
Field trip: casino game odds
There is nothing to strip out of a casino game, because the price never moves. The edge is baked into the rules, and one tool reads all of them: multiply each payoff by its odds of happening, then add. A roulette number pays 35-to-1 and lands once every 38 spins, so
That is the toll on every spin, and nearly every other bet on that wheel comes to the same number. (One exception, the five-number basket, and it is worse: −7.89%.)
Seven games below. Two of them can go positive if you are good enough: blackjack with a count, and poker, where you are playing the table rather than the house. The other five stay negative at any stake, under any system, forever.
Blackjack Strategy & Card CountingThe one house game with memory. Basic strategy trims the edge to about 0.5%; a running count can push it past zero.
Poker Strategy: Skill vs. the RakeThe opponent is the table, not the house (minus the rake). Pot odds, position, and where the skill premium shows up.
Roulette Odds: 5.26% a SpinTwo green pockets are the whole edge: −5.26% on nearly every American-wheel bet, −2.70% on a single-zero wheel.
Craps Odds: Good Bets, Sucker BetsThe pass line is −1.41%. Ten feet away on the same layout, “Any 7” is −16.67%. Same dice.
Slot Machine OddsThe edge hides inside the machine’s return-to-player: −3% to −12%, resolved as often as 600 times an hour.
Baccarat Odds: Banker, Player, TieBanker at −1.06% is among the lowest edges on the floor. The Tie bet, at about −14%, is not.
Keno Odds: The Worst on the FloorA lottery that pays pennies on the true odds. The edge runs 20% to 35%, the widest in the building.
References
Not lessons: the lookup pages. Open them whenever a word or an equation needs checking.
The calculators
All free, no signup, and each one prints its working next to the answer. They run the same math library as the rest of the site: teachersbettextbook, MIT-licensed, on PyPI. If you want to check us, you can check us line by line in Python.