“Fermi Calculation Examples”, 2019-03-29 (; backlinks):
Fermi estimates or problems are quick heuristic solutions to apparently insoluble quantitative problems rewarding clever use of real-world knowledge and critical thinking; bibliography of some examples.
A short discussion of “Fermi calculations”: quick-and-dirty approximate answers to quantitative questions which prize cleverness in exploiting implications of common knowledge or basic principles in given reasonable answers to apparently unanswerable questions.
Links to discussions of Fermi estimates, and a list of some Fermi estimates I’ve done.