[timbit42]

If you study the various versions, Masoretic, Samaritan and Septuagint, a number of the ages differ. At some point someone reduced Methuselah's age because it would have meant he survived the flood, which didn't fit their interpretation of the Noah story.

That said, most of the ages in Genesis were incorrectly translated from Sumerian cuneiform due to them having different numbering systems for different things which reused some of the same symbols (why would anyone find that confusing???). Whoever copied those numbers into the Bible used the wrong numbering system. If you convert back and use the numbering system for dates and time, you get regular ages. For example, Methuselah didn't live 969 years, but instead, 85 years.