A little Torah question, WHAT IS GOING ON IN CHAPTER 5 OF GENESIS

I am choosing to revisit studying the Torah to make sense of the world and my own life, and I highly recommend it to anyone here. It has provided me with a lot of insight, and answered a lot of questions I have.

But chapter 5 HAS LEFT ME WITH SO MANY QUESTIONS. WHY DO WE KEEP TALKING ABOUT EVERYONE’S AGE?? WHY IS EVERYONE SO OLD??? WHY DO THEY MENTION THIS 9 TIMES??? IS THIS A MATH WORD PROBLEM????

1. When Adam had lived 130 years, he begot a son in his likeness after his image, and he named him Seth. After the birth of Seth, Adam lived 800 years and begot sons and daughters. How old is Adam now? (Show your work for credit):

I would genuinely love to know what the point of this chapter is because right now, it’s just very odd to me.