How to play
Open the dated daily puzzle and read the first question together with its unit and explanatory note. An amount per second, a yearly total and a volume are different tasks. Where the game offers a unit switch, confirm the selected unit before entering a number.
Break the quantity into smaller pieces you can estimate. Type a positive numerical guess into the answer field. You can correct digits with Backspace and use the built-in calculator or scratch pad to work through a multiplication without leaving the question.
Press Enter or choose Lock it in to submit. Read the revealed answer, its cited source and the too-high or too-low feedback. The score is expressed as a multiple: an exact estimate is 1×, and a result nearer 1× is better than a larger miss.
Continue through Question 2 and Question 3, then open the results. The summary keeps the individual question scores alongside the combined daily score. Use the question controls to revisit a reveal; sharing or opening the archive is optional rather than part of submitting an answer.
What makes this game different
Fermi rewards numerical closeness, not an unusual valid category response. A familiar fact can provide an excellent starting point if you scale it carefully. Unlike a quiz with a single exact-answer threshold, its ratio feedback helps distinguish a reasonable estimate from an error of an entire order of magnitude.
A better way into your next round
Write down the unit before doing arithmetic, then make a rough range. For an annual quantity, a per-day estimate multiplied by the number of days can be easier to reason about. Check whether the question includes a particular year or definition that changes the population or activity being counted.
Use the reveal to inspect your assumptions rather than merely memorise a number. If the estimate is far out, look for a missing conversion or an extra factor of ten. The calculator helps with arithmetic, but it cannot decide whether your starting assumptions fit the question.
Where to play
The publisher’s full browser game runs in the game area above, with an option to open Fermi.gg separately. Numeric entry, Backspace and Enter submission are supported. The calculator accepts typed expressions, and Escape closes it. Publisher accounts, saved progress and privacy practices remain separate from Dleindex.