Was Enoch the sixth or the seventh from Adam? Bible Contradictions

This Bible contradiction is from the Skeptic's Annotated Bible.

Verses

And Adam lived an hundred and thirty years, and begat [a son] in his own likeness, after his image; and called his name Seth:

And the days of Adam after he had begotten Seth were eight hundred years: and he begat sons and daughters:

And all the days that Adam lived were nine hundred and thirty years: and he died.

And Seth lived an hundred and five years, and begat Enos:

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

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

And Enos lived ninety years, and begat Cainan:

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

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

And Cainan lived seventy years, and begat Mahalaleel:

And Cainan lived after he begat Mahalaleel eight hundred and forty years, and begat sons and daughters:

And all the days of Cainan were nine hundred and ten years: and he died.

And Mahalaleel lived sixty and five years, and begat Jared:

And Mahalaleel lived after he begat Jared eight hundred and thirty years, and begat sons and daughters:

And all the days of Mahalaleel were eight hundred ninety and five years: and he died.

And Jared lived an hundred sixty and two years, and he begat Enoch:

Adam, Sheth, Enosh,

Kenan, Mahalaleel, Jered,

And Enoch also, the seventh from Adam, prophesied of these, saying, Behold, the Lord cometh with ten thousands of his saints,