The exegetical options are to take a presumed etymology from חמש, "five," or to look at other contexts in which חֲמֻשִׁים turns up. Note that Aquila does not etymologize here (unlike Theodotion and LXX, who connect חמש with the numeral). Aquila and Symmachus have similar interpretations based on other military contexts for this word: Symmachus's equivalent is used once by LXX at Num 32:21 for חָלוּץ.

For ExodB's "fifth generation" (πέμπτη ... γενεᾷ), Theod reads πεμπταίζοντες, "on the fifth day." But the Heb. more commonly means "armed in battle array" (cf. Targ Ps-J, Targ Onq, Syr, Vulg; Aq ἐνωπλισμένοι, Sym ὁπλῖται; cf. LXX Josh 1.14; 4.12; Auld 2005, 117; see BS 1989, 160). Exod is here consistent with 6.16 ff., which indicates four generations of Israelites' stay in Egypt.

A certain amount of smoothing and harmonisation on the translational level has been noted. For instance, in the account of the theophany at Sinai, the Greek clarifies when it will be safe for the people to touch the mountain (Exod. 19.13). Elsewhere the translation says that Moses stretched out his staff towards the heavens rather than over the whole land of Egypt (10.13), and explains חמשים "prepared for battle" (13.18) to mean "in the fifth generation" (πέμπτῃ δὲ γενεᾷ) on the basis of 6.16-20 (Wevers, "How the Greek").