Genesis 5:9 Meaning

7And Seth lived after he begat Enos eight hundred and seven years, and begat sons and daughters:

8And all the days of Seth were nine hundred and twelve years: and he died.

9And Enos lived ninety years, and begat Cainan:

10And Enos lived after he begat Cainan eight hundred and fifteen years, and begat sons and daughters:

11And all the days of Enos were nine hundred and five years: and he died.