Roman Numerals +

(Latin numbers as cardinals, "quantities"; and as ordinals, "showing order" or "designating a place in an ordered sequence")

I; unus, primus
Cardinal: one, Ordinal: first
II; duo, secundus
Cardinal: two, Ordinal: second
III; tres, tertius
Cardinal: three, Ordinal: third
IV; quattuor, quartus
Cardinal: four, Ordinal: fourth
V; quinque, quintus
Cardinal: five, Ordinal: fifth
VI; sex, sextus
Cardinal: six, Ordinal: sixth
VII; septem, septimus
Cardinal: seven, Ordinal: seventh
VIII; octo, octavus
Cardinal: eight, Ordinal: eighth
VIII; novem, nonus
Cardinal: nine, Ordinal: ninth
X; decem, decimus/decumus
Cardinal: ten, Ordinal: tenth
XI; undecim, undecimus
Cardinal: eleven, Ordinal: eleventh
XII; duodecim, duodecimus
Cardinal: twelve, Ordinal: twelfth
XIII; tredecim, tertius decimus
Cardinal: thirteen, Ordinal: thirteenth
XIV; quattuordecim, quartus decimus
Cardinal: fourteen, Ordinal: fourteenth
XV; quindecim, quintus decimus
Cardinal: fifteen, Ordinal: fifteenth