What Am I Riddles

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?

Question: You can rest on my pad without touching the keys.
I will sing all month long as long as you pay your fees.

What am I?