Question: If Noah was 500 when he was told to build the ark and 600 when he & 3 sons and all the wives got on board with the animals, how many other children, grandchildren, great-grandchildren did he leave behind? I would imagine that he had many more than just 3 sons in 500 years, yes??
Answer: It is possible Noah had children prior to Shem, Ham and Japheth. If he did, those children must not have been walking with God. Genesis 5:32 seems to indicate that he had Shem, Ham and Japheth either as triplets when he was 500 or individually around Noah's 500th year. The flood occurred in Noah's 600th year (Gen. 7:6). Based on Genesis 11:10, Shem was 98 years old at the time of the flood. We only know what these verses tell us however.