Objective
Each round has five Fermi questions built from real measurements — lengths, masses, areas, volumes, costs, times, speeds and counts. You do not need the exact figure. You need a careful estimate.
Scoring (10 points per question)
- 10 points if you are within 10%
- 7 points within 20%
- 5 points within 35%
- 3 points within 50%
- 2 points within a factor of 2
- 1 point within a factor of 10 (the right order of magnitude)
A round is a win at 20/50 or more. All five within 10% is a perfect envelope (50/50).
How to estimate
- Split each quantity into a number between 1 and 10 and a power of ten.
- Divide the larger by the smaller. Keep track of the powers.
- Volume questions about packing objects use a 0.64 packing factor when both things are solid objects.
Daily challenge
Everyone receives the same five Classic-level questions. They reset at midnight UK. The first win of the day counts for the league and your streak.