In the past week, I looked at this idea again and built a very simple site which gives you a new Fermi estimation question every day:
How many new cars were sold in the US in 2024?; How many humans have ever lived (including those currently alive)?; How many chickens are slaughtered for meat every year?
To win, you need a guess within ±20% of the correct answer. For this you have a maximum of 6 tries and after each guess, you can see if your answer was too high or too low.
Fermi questions are, by the way, a wonderful way to build up your own numeracy and sense for order-of-magnitude differences. Douglas Hofstadter proposed using them for exactly this reason in his essay "Number Numbness, or Why Innumeracy May Be Just as Dangerous as Illiteracy" (https://gwern.net/doc/math/1982-hofstadter-2.pdf)