I'm not generally inclined to do math, but I made an attempt to see how many generations Adam lived to see. As I calculated, Adam was 874 years old when Lamech wsa born, and did not live to see Noah's birth. Lamech would have been 56 when Adam died. Again, if my math is right, he lived to see the complete degradation of his race. When I started trying to figure this out, I was thinking what a blessing it was that he got to see and know his grand- and great- and great-great, etc. but when I realized the length of time he was alive, i wonder if it wasn't more of a burden than a blessing. Just one more thng, if the great flood occurred when Methuselah died, the earth was 1,686 years old at the time of the flood, as Adam was 687 when Methuselah was born. If anyone wants to check my numbers, please feel free - see disclaimer above.