5.0

 Discoverd via FiveBooks on math article by Alex Bellos
https://fivebooks.com/best-books/alex...
I love goofy math books; this absolutely charmed me. We encounter, in short vignettes set in 13th century Baghdad, several numerical tricks and puzzles: How can three brothers divide 35 camels according to the terms of their father's bequest? How can a merchant discover which of eight pearls is lighter than the others, given a balancing scale that can be used only twice? Perfect numbers are defined by releasing three birds from a cage of 499; amicable numbers are demonstrated by poems written on a wall in red and black letters. Myths about the origin of chess, about the death of Archimedes and Eratosthenes, and passages on ethical issues and the wonder of math, apart from its usefulness, appear as well. All is set in a Stranger Comes To Town plot; it's been compared to 1001 Arabian Nights, if Scheherazade were a mathematician.
FMI see my blog post at A Just Recompense.