purity Markings on gold jewelry

The majority of gold items will be marked with a gold purity stamp.  Typically these will be 10k, 14k, and 18k.  But what do these marks really mean?  Pure gold is 24k.  So if an item is 10k, 14k, or 18k the maker is saying that the gold content is 10/24ths, 14/24ths, or 18/24ths gold, the remaining portion being allow metals.  As fractions 10k gold is .417 or 41.7%; 14k is .585 or 58.5%; 18k is .750 or 75%.  It is also not uncommon, particularly for european made jewelry items, to see the mark represented as 417, 585, or 750.