when to use 'doua' vs. 'doi'?
doi is for masculine nouns, and două is for feminine nouns. Numbers higher than two don't make that distinction.
Also, for neutral nouns, you also use "doua" in plural (while using "un" in singular).
"Leu" is also the currency of both Romania and Moldova, though they are different. The only thing they have in common is the name.