Where does “пятьдесят” come from?
пятьдесят (Russian) comes from Russian де́сять, from Old Church Slavonic десѧть, from Proto-Slavic desętь, from Proto-Balto-Slavic *déśimt, from Proto-Indo-European déḱm̥t — ten.
пятьдесят (Russian): fifty
Ancestry of “пятьдесят”, step by step
Words derived from “пятьдесят”