Found out a 16 penny nail is actually 3 and a half inches, not 16 of anything
Spent 20 minutes last week explaining to my helper why the numbers on nail boxes don't match lengths, and it turns out the old "penny" system goes back to 15th century England when 100 nails cost 16 pence. Anyone got a simple way to explain that to a green kid without sounding like a history teacher?