After Enosh was 90 years old, he had a son named Kenan.
Lamech was the son of Methuselah. Methuselah was the son of Enoch. Enoch was the son of Jared. Jared was the son of Mahalaleel. Mahalaleel was the son of Cainan.
So Seth lived a total of 912 years; then he died.
After Kenan was born, Enosh lived 815 years and had other sons and daughters.