'Eighty' in the Bible

Now Barzillai [was] very old, {eighty years old}. Now he had provided the king [with food] while he [was] staying at Mahanaim, for he [was] a very wealthy man.

I [am] eighty years old today. Can I discern between good and bad? Or can your servant taste what I eat or what I drink? Or can I still hear the voice of singing men and women? Why should your servant be a burden any longer to my lord the king?