Quote Originally Posted by Antonio1986 View Post
When I started to believe that I was becoming expert in Decimals the number 0.021 occured and I said: сегодняшний валютный курс двадцать один тысячных.
But I have a suspision that the client said двадцать одна тысячная
Yep, it's двадцать одна тысячная

Other examples:

2.3 - две целых три десятых
100.07 - сто целых семь сотых

And like that