Umberto Cassuto takes a far different approach, from that of the kabbalists cited in recent posts, to numbers in the bible. He focuses instead on “the sexagesimal system, which was in general use in the ancient East” (A Commentary on the Book of Genesis, part two: from Noah to Abraham, p.32).
Cassuto’s commentary on the measurements of Noah’s ark are brief, and not terribly illuminating, simply noting that the height of thirty cubits is “half of sixty, the fundamental number of the sexagesimal system” (p.63). His numerical commentary on other verses is so extensive, however, as to prompt apology: “The reader will, I trust, forgive me for devoting to this subject about two pages of dry, analytical calculations” (p.255).
Here is one part of the subsequent remarks on the generations from Noah’s son Shem to Abraham’s father, Terah:
From Arpachshad to Nahor, the age of the patriarchs at the time of the birth of the first son is fixed, as we have stated, round about thirty, that is, half a unit of sixty years, or six units of sixty months. In three cases it is exactly thirty, and in four instances it is slightly more or less, namely, +5, +4, +2, -1, making an algebraic total of +10 years, that is, two units of sixty months. In the generation of Terah, the age rises again and reaches seventy years — fourteen units of sixty months.
— Cassuto, A Commentary on the Book of Genesis, part two: from Noah to Abraham, Jerusalem: Magnes, 1992. p.256