What Am I Riddles

Question: My memory is good, nay, more like perfect Yet I only remember two things.

Question: I attach to your hip and I sing all day.
All I want to do is play.

Question: he is a king who's good at measuring stuff.

Question: I float when I am born, lay down when I am alive, and run when I am dead. What am I?

Question: Sometimes, I leave you with “mixed” feelings. More times than not, I teach you a lesson. I give what I didn’t create. What am I?