https://ocw.mit.edu/courses/res-6-011-the-art-of-insight-in-...
https://ocw.mit.edu/courses/res-6-011-the-art-of-insight-in-...
Also see Maths on the Back of an Envelope: Clever ways to (roughly) calculate anything. by Rob Eastaway - https://aperiodical.com/2019/11/review-maths-on-the-back-of-...
Related is How to Read Numbers: A Guide to Statistics in the News (and Knowing When to Trust Them) by Tom Chivers and David Chivers - https://en.wikipedia.org/wiki/How_to_Read_Numbers
Finally, the old Soviet books by Yakov Perelman (https://mirtitles.org/?s=Yakov+Perelman) named Physics for Entertainment, Mathematics for Fun etc. also fall under the same category and are a good read.
Bonus: https://en.wikipedia.org/wiki/Back-of-the-envelope_calculati... Follow other links like "Guesstimate" from the "See also" section.