zero

Borrowed from English zero, French zéro, Italian zero, Spanish cero.


non

From English nine, German neun, ultimately from Proto-Indo-European *h₁néwn̥. In length from English nona-, French nona-, Italian nono, Spanish nono.


du

From Esperanto du, from French deux, Spanish dos, Italian due, ultimately from Proto-Indo-European *dwóh₁.


kin

From French cinq, Spanish cinco, Italian cinque, ultimately from Proto-Indo-European *pénkʷe.


un

Borrowed from French un, Italian un, Spanish un.


tri

From Esperanto tri, from English three, French trois, German drei, Spanish tres, Italian tre, Russian три (tri), all ultimately from Proto-Indo-European *tréyes.


cent

Borrowed from English cent, French cent, German Cent, Italian cent, Russian цент (cent), Spanish centavo.


ok

From Esperanto ok, from Latin octo, ultimately from Proto-Indo-European *oḱtṓw.


mil

Borrowed from Esperanto mil, French mille, Italian mille, Spanish mil, from Latin mīlle.


dek

From Esperanto dek, from Latin decem, ultimately from Proto-Indo-European *déḱm̥.


sis

From English six, French six, German sechs, Spanish seis, Italian sei, Russian шесть (šestʹ), all ultimately from Proto-Indo-European *swéḱs.


biliardo

Borrowed from English billiard, French billiard, German Billiarde, Italian biliardo, Russian биллиард (billiard), Spanish billardo. Considered derived from biliard + -o, thus the special placement of the stress.


quar

Borrowed from Esperanto kvar, French quatre, Italian quattro, Spanish cuatro, ultimately from Proto-Indo-European *kʷetwóres.


sep

From Esperanto sep, from Latin septem, ultimately from Proto-Indo-European *septḿ̥.


quantesma

Derived from quanta (“how much”) + -esma (“-th”).

Quantesma dio di la monato?