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.
- One Very Full Truck
- One Very Long Walk
- Our Galactic Neighborhood
- Packed for the Move
- Packing the Wide-Body
- Paper Stack to the Ceiling
- Paying for the Fast Lane
- Pet Dogs in America
- Phone Charges in a Lifetime
- Power Across a Continent
- Retail Trading Friction
- Showers in a Lifetime
- Smartphones Sold Each Year
- Soda Cans in a Refrigerator
- Steps in a Year
- Supplying the Courts
- Teachers of New York City
- The Air Above Us
- The Body by Numbers
- The Body's Hidden Network
Showing 101 to 120 of 158 results
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.