After he became the father of Methuselah, Enoch walked faithfully with God 300 years and had other sons and daughters. (NIV)
Enoch walked [in habitual fellowship] with God after the birth of Methuselah 300 years and had other sons and daughters. (AMP)
And Enoch walked with God after he begat Methuselah three hundred years, and begat sons and daughters: (KJV)