NUMERALS
Cardinal Numbers (1-10):
εἱς, μία, ἓν = One
δύο = Two
τρεῖς, τρία = Three
τέσσαρες, τέσσαρα = Four
πέντε = Five
ἓξ = Six
ἑπτά = Seven
ὁκτώ = Eight
ἐννέα = Nine
δέκα = Ten
Numbers 1-4 change their endings depending on their role in the sentence, the rest are indeclinable.
Here they are below:
One / εἷς (3-1-3 declension):
* Note: εἷς (one) is similar to εἰς (into); ἓν (one) is similar to ἐν (in) —> Only the breathing distinguishes between them.
Two / δύο:
Three / τρεῖς (3 - 3 declension):
Four / τέσσαρες (3 - 3 declension):
Ordinal Numbers (1st-10th):
πρῶτος, -η, -ον = First
δεύτερος, -α, -ον = Second
τρίτος, -η, -ον = Third
τέταρτος, -η, -ον = Fourth
πέμπτος, -η, -ον = Fifth
ἓκτος, -η, -ον = Sixth
ἓβδομος, -η, -ον = Seventh
ὂγδοος, -η, -ον = Eighth
ἒνατος, -η, -ον = Ninth
δέκατος, -η, -ον = Tenth
They decline like 2-1-2 adjectives (like σοφός), with δεύτερος like φίλιος with the alpha in the feminine.
Ordinal numbers work like any adjective - sandwiched in an article or with a repeated article as the noun it agrees with.