John Goldingay (Fuller Theological Seminary) is one of our greatest Old Testament scholars. In his Genesis for Everyone book Goldingay gives a suggestion about how to interpret the long ages of the patriarchs mentioned in Genesis chapter 5. For example, all the days that Adam lived came to 930 years.
Remember the importance, in interpreting any text, of identifying the literary genres involved.
"We do not really know how to interpret their ages. With big numbers in the Old Testament, more “realistic” numbers may have come to be misunderstood; perhaps an earlier version of this family history had more realistic numbers. But something is going on here beyond simply the ascribing of preternaturally long lives to people; these men don’t even father their first child until they reach the kind of age when we would expect them to die or to be well past fathering. (There are Middle Eastern records that give much more wildly unrealistic numbers for the ages of various kings.)
Whatever their background, the numbers as they appear in Genesis suggest something striking. Adam lives to be 930; Seth, to be 912; Enosh, to be 905; Kenan, to be 910; Mahalel, to be a mere 895; but Jared, to be 962. Now, when I hear of someone who lived until they were 99, I am inclined to think, “Oh what a shame she didn’t live until she was 100.” There is something about that magic number. In Genesis 5, the magic number is 1000 (compare the millennium in Revelation 20). But no one quite makes it. We will soon read of the famous Methuselah, who almost did; he reached 969. But he, too, died before reaching the magic number. The impression that the numbers are significant will be confirmed by two others that come in Genesis 5: 21– 31. Enoch lives 365 years, the number of days in a year; he indeed realizes a full life. Lamech lives 777 years, another number of completeness. As the number of days in the week, seven stands for completeness, so 777 suggests three times completeness (contrast 666, the number of the beast in Revelation 13: 17– 18)."
- John Goldingay, Genesis for Everyone: Part 1 Chapters 1-16, p. 86.