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Quant interviews, one square a day.

A daily puzzle book for quant interviews. 3,500+ problems in probability, brainteasers, options, statistics, code and mental math, every one with a worked explanation, plus timed games built like the online tests trading firms send.

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For trader, researcher and developer interviews. Starts at first-course probability and climbs to superday-hard.

1 Across

Try a clue

30

Fractions like 3/8 are fine.
Problems
3,500+
With worked solutions
Every one
Games and tests
6
New daily puzzle
Every day

Open the book anywhere

Browse all problems

Every problem comes with the method, not just the answer. Pick a topic to see one worked through.

How it works

  1. 1

    Solve today's puzzle

    One new problem every day. Solve it and that day's square on your calendar turns yellow. Miss a day and a streak freeze can cover it.

  2. 2

    Train what you miss

    Missed problems come back after 1, 3 and 7 days. Follow a study track, or practice at your level. Every problem shows the method, step by step for the hard ones.

  3. 3

    Test yourself under the clock

    Take a 20-minute mock assessment, then watch your rating in each skill climb on your stats page.

Practice under real interview pressure

See all games
1

Mock assessment

20 questions in 20 minutes across mental math, sequences, probability and markets knowledge. Scored at the end, like an online test.

20 questions · 20 minTake it 2

Speed Math

Arithmetic against the clock. Pick operations, difficulty and length, then see which operation slows you down.

2 min rounds · beat your bestPlay 3

Puzzle Rush

Three minutes, three strikes. Every right answer makes the next problem harder.

3 min · 3 strikesPlay 4

Make a Market

Quote a bid and an ask on a number you don't know, then get coached on your width and direction.

6 quotes · about 5 minPlay 5

Betting Table

A coin with an edge and a bankroll. Learn Kelly sizing by watching what over-betting does.

30 flips · vs a Kelly bettorPlay 6

Desk Quiz

Rapid questions on Greeks, put–call parity, regression and Python gotchas.

10 questions · about 3 minPlay

Questions

Is Edge free?

Yes, every problem, game and test, with no ads.

Do I need an account?

No. Practice as a guest and your progress stays in your browser. An account syncs it across devices and puts you on the weekly leaderboard.

Where do the problems come from?

They're written for Edge: hand-written classics in our own words, plus generators that create many versions of well-known problem types with every answer computed exactly. None are copied from any firm.

Is Edge affiliated with a trading firm?

No. Edge is independent. Firm names only ever describe common interview formats.

Can I use it on my phone?

Yes. It works in any mobile browser and can be added to your home screen like an app.

What happens to my data?

No ads, no trackers, no cookies. You can download or delete your data at any time. Read the privacy policy.

Your first square is waiting.

A free account syncs your streak across devices and puts you in the weekly league.

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