Herbert Weir Smyth, A Greek Grammar for Colleges

a. Distributives proper, answering the question how many each? are wanting in Greek. Instead, ἀνά, εἰς, and κατά, with the accus., and compounds of σύν with, are used: κατὰ δύο or σύνδυο two by two, two each (Lat. bini). The cardinals are often used alone, as ““ἀνδρὶ ἑκάστῳ δώσω πέντε ἀργυρίου μνᾶς” singulis militibus dabo quinas argenti minas” X. A. 1.4.13.

b. Multiplicatives in -πλοῦς -fold (from -πλοος, Lat. -plex), ἁπλοῦς simple, διπλοῦς twofold, τριπλοῦς threefold, πολλαπλοῦς manifold.

c. Proportionals in -πλασιος: διπλάσιος twice as great or (plur.) as many, πολλαπλάσιος many times as great (many).

d. διττός means double, τριττός treble (from διχ-ιος, τριχ-ιος 112).

N.—Multiplication.—Adverbs answering the question how many times? are used in multiplication: τὰ δὶς πέντε δέκα ἐστίν twice five are ten. See also 347 N.

e. Abstract and Collective Numbers in -άς (gen. -άδ-ος), all feminine: ἑνάς or μονάς the number one, unity, monad, δυάς the number two, duality, τριάς trinity, triad, δεκάς decad, decade, εἰκάς, ἑκατοντάς, χι_λιάς, μυ_ριάς myriad, ἑκατὸν μυ_ριάδες a million. Also in -ύς: τριττύς (-ύος) the third of a tribe (properly the number three), τετρακύς.

f. Adjectives in -αῖος, answering the question on what day? δευτεραῖος (or τῇ δευτεραίᾳ) ἀπῆλθε he departed on the second day.

g. Adverbs of Division.—μοναχῇ singly, in one way only, δίχα, διχῇ in two parts, doubly, τριχῇ, τέτραχα, etc., πολλαχῇ in many ways, πανταχῇ in every way.