a) To denote so much each, so many apiece; as,—
bīna talenta eīs dedit, he gave them two talents each.
b) When those nouns that are ordinarily Plural in form, but Singular in meaning, are employed in a Plural sense; as,—
bīnae litterae, two epistles.
But in such cases, ūnī (not singulī) is regularly employed for one, and trīnī (not ternī) for three; as,—
ūnae litterae, one epistle; trīnae litterae, three epistles.
c) In multiplication; as,—
bis bīna sunt quattuor, twice two are four.
d) Often in poetry, instead of the cardinals; as,—
bīna hastīlia, two spears.