Answer:
Why is it so easy to weigh fish?
I am a king who’s good at measuring stuff. What am I?
I'm a precious stone in a pack of cards. What am I?
I have a little pool with two layers of wall around it. One white and soft and the other dark and hard. Amidst a light brown grassy lawn with an outline of a green grass.
As a state in America I am round on both sides and high in the middle.
It can be cracked, It can be made, It can be told, it can be played. What is it?