Fermi Questions
Order-of-magnitude estimation questions used in quant and trading interviews, break the unknown into parts, reason to a defensible answer, and track your progress as you solve.
- A Stadium-Sized Puzzle
- A Tower at Full Tilt
- A Towering Animal
- A Towering Grazer
- A Trailer Packed Tight
- A Very Crowded City
- A World of Stays
- A Year of Drinking Water
- A Year on the Road
- Across an Iconic Crossing
- An Airborne Packing Puzzle
- An Early-Years Market
- An Interview-Room Puzzle
- An Unusual Pool Party
- An Unusual Swimming Pool
- An Urban Coffee Network
- Assembly Lines at Scale
- Awake at 3am in Chicago
- Before the Interview
- Behind the Walls
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What are Fermi questions?
Fermi questions ask you to estimate a quantity you can’t look up, like “how many piano tuners are there in Chicago?”, by breaking it into parts you can reason about and combining sensible assumptions. Trading and quant interviewers love them because they reveal how you decompose a problem, handle uncertainty, and sanity-check a number under pressure.
On Tradermath, each question is graded by order of magnitude: get within a factor of ten and you’re on track. Work through the curated set, reveal hints when you’re stuck, and compare your estimate against a full worked solution to build the instinct that matters most in interviews.