Estimania

How to play

1. 01

   Read the question

   Every question has a numerical answer. Some are Fermi questions, meant to be reasoned out rather than known.

2. 02

   Enter your guess

   Type your best numerical estimate.

3. 03

   See how close

   You score 0 to 100 on a logarithmic scale: a perfect guess scores 100, and being off by a factor of 10 or more scores 0.

4. 04

   Learn something

   Every answer comes with a short explanation. After five questions, your total out of 500 is revealed.

Good to know

• Ratio, not difference. Being 2× off scores the same whether the answer is 5 or 5 billion, and guessing too high or too low by the same factor costs the same.
• Percentages are stricter. Questions with a percentage answer are scored on the odds, so near misses cost more.
• Narrow answers too. Some questions are scored more strictly because their answer can only fall in a narrow range. On those, being 3× off already scores 0.