The functions of ordinal numerals in a sentence.
As a rule ordinal numerals are used as attributes.
“No, this is my firstdance,” she said. (Mansfield)
Almost immediately the band started and her secondpartner seemed to spring
from the ceiling. (Mansfield)
But they may also be used as subject, as predicative and as object.
Then, advancing obliquely towards us, came a fifth.(Wells) (SUBJECT)
Sooner or later, someone is going to tell you about that damned river, so I
might as well be the first.(Wilson) (PREDICATIVE)
...she noted a scar on his cheek, another that peeped out from under the hair of
the forehead, and a thirdthat ran down and disappeared under the starched
collar. (London) (OBJECT)
In fractional numbers the numerator is a cardinal and the denominator is a substantivized ordinal: two-thirds, three-sixths.
Decimal fractions are read in the following way: 7.58 — seven point (decimal) five eight.