Fermi

Fermi is a daily estimation puzzle where your mission is to answer three impossible questions using napkin math and intuition in one guess each, scored on how close you get as a multiple of the real answer.

Each day brings three Fermi questions: the kind of wild numerical riddles that have no obvious answer but can be cracked with rough calculation and educated guessing. How many Oreos are eaten in the US each day? How many steps does a mail carrier walk in a year? No Googling allowed. Just your brain, some back-of-napkin logic, and a built-in calculator if you need it.

• You get 3 questions and 1 guess per question.
• Type your estimate and lock it in. No second chances.
• Your score is how far off you were as a multiple of the real answer. Nail it and you score 1×. Off by double, that's 2×. Off by ten times, 10×. Lower is better.
• After each guess, you see the real answer, some example math to get there, and how you stacked up against other players.
• Your daily score is the average of your three question scores.
• A new set of three questions drops every day at midnight ET.

Why we like it:

• ✅It rewards creative thinking over trivia knowledge.
• ✅Even wild guesses teach you something about scale and estimation.
• ✅The scoring system is forgiving enough that you can have fun without being perfect.

Hint: Break big questions into smaller chunks. Estimating total iPhones ever made? Start with yearly sales, multiply by years, and adjust for growth. You won't nail it, but you'll get closer than a random stab.