He also writes that "no attempt has been made to explain why a tally of something should exhibit multiples of two, prime numbers between 10 and 20, and some numbers that are almost multiples of 10.
V knjigi " How Mathematics Happened: The First 50,000 Years", Peter Rudman trdi, da bi se razvil koncept praštevil le približno po konceptu delitve, ki datira po 10.000 pred našim štetjem, s praštevili se verjetno niso razumeli do približno 500 pred našim štetjem.