Ordinal Numbers

I hope you're confident with cardinal numbers. So now go on to ordinal ones. Ordinal indicates the order in which things/ people/ events are placed.
Cardinal number 1 comes 1st in line.
Cardinal number 2 is 2nd in the order
Cardinal number 109 comes in 109th place.

Ordinal numbers are adjectives and as such vary in form

(masculine, feminine, neuter)
(singular, plural)
( nominative, accusative, dative, genitive, vocative)

according to the noun they belong to.

1st ὁ πρῶτος , ἡ πρώτη , τὸ πρῶτον Note that the feminine ending, whether α or η is always long and the stress will always fall on the penult.
2nd ὁ δεύτερος, ἡ δευτέρα, τὸ δεύτερον
3rd ὁ τρίτος, η, ον
4th ὁ τέταρτος, ἡ τετάρτη, τὸ τέταρτον
5th ὁ πέμπτος, η, ον
6th ὁ ἕκατος, ἡ ἑκάτη, τὸ ἕκατον (comes from ἕξ pronounced ks)
th ὁ ἕβδομος, ἡ ἑβδόμη, τὸ ἕβδομον
8th ὁ ὄγδοος, ἡ ὀγδόη, τὸ ὄγδοον
9th ὁ ἔνατος, ἡ ἐνάτη, τὸ ἔνατον
10th ὁ δέκατος, ἡ δεκάτη, τὸ δέκατον

According to old country laws:
ὁ πρῶτος υἱὸς got all
ὁ δεύτερος, ὁ τρίτος καὶ οἱ λοιποί got nothing
ἡ πρώτη ἡμέρα in a new job is τὸ ἥμισυ exciting τὸ ἥμισυ daunting and confusing
ἡ δευτέρα ἡμέρα is already less stressful
τρεῖς εἰσιν αἱ Μοῖραι the Fates
ἡ πρώτη, Κλωθὼ ὀνόματι is there at our birth spinning the thread of life
ἡ δευτέρα, Λάχεσις ὀνόματι weaves the thread into the fabric of our lives
ἡ δὲ τρίτη , ἡ Ἄτροπος decides when our thread is to be cut.