If my claim (plus what you added to it) is wrong, it can take a hike.
The Bible said it, that settles it.
And the Bible says ...
Genesis 5:27 And all the days of Methuselah were nine hundred sixty and nine years: and he died.
In fact, let's go deeper.
Genesis 5:21 And Enoch lived sixty and five years, and begat Methuselah:
Genesis 5:22 And Enoch walked with God after he begat Methuselah three hundred years, and begat sons and daughters:
Genesis 5:25 And Methuselah lived an hundred eighty and seven years, and begat Lamech:
Genesis 5:26 And Methuselah lived after he begat Lamech seven hundred eighty and two years, and begat sons and daughters:
Genesis 5:27 And all the days of Methuselah were nine hundred sixty and nine years: and he died.
(And don't think I don't know what you're talking about with that "base ten" stuff.)