Old Testament readings use the Septuagint , the Scripture the apostles quoted. Masoretic numbering shown for reference.Learn why
KJV

Genesis 5:13

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

Parallel Translations

LXXView canonical →
And Cainan lived after his begetting Maleleel, seven hundred and forty years, and he begot sons and daughters.
Brenton's Septuagint Translation
LXX2012View canonical →
And Cainan lived after his begetting Maleleel, seven hundred and forty years, and he begot sons and daughters.
Septuagint in American English (2012)
WEBView canonical →
Kenan lived after he became the father of Mahalalel eight hundred forty years, and became the father of other sons and daughters
World English Bible