This is the first time I meet a monetary system that is not based on the relation
100 - 50 - 20 - 10 - 5 - 1 - 0.50 - 0.25 - 0.10 - 0.01
As other people have mentioned, although not explicitly, the British pound (and the Euro) have different sub-unit currency subdivisions, ie:
100 50 20 10 5 2 1
http://www.royalmint.com/talk/specifications.asp http://www.eurocoins.co.uk/ireland.html
as opposed to the US model:
100 50 25 10 5 1
http://www.usmint.gov/faqs/circulating_coins/index.cfm?action=faq_circulating_coin
Of course, the US has to give their coins cutesy names, just to confuse people; a habit that's thankfully died out here (cf previous discussion of florins).
I vaguely recall seeing a survey that recommended an 18/100 unit coin as the optimum for currencies, but the mental arithmetic would be horrific. I don't know if they pronounced on whether 20 is better than 25 or not, but it's interesting that the US doesn't issue 25 dollar bills.
-- :: paul :: compiles with canadian cs1471 protocol
