Simple to get the ages, for example with Adam he lived 130 years and had a son Seth, then live another 800 before he died. So he lived altogether 130+800=930 years.
The verses also show how many generations people lived. Adam would have still been alive at the time of Enoch (6 generations later). During his life Adam surely taught his ofspring, who ever had a heart to listen, about his experience with God. The fact that Enoch "walked with God" and "was taken" shows that even during the time when mankind was falling farther into sin and separation from God, God still had men whom he cared for and fellowshipped with. ?