Me: Kai, will you do me a favor?
Kai: Sure.
Me: Will you run upstairs and get me a diaper?
Kai: Aaah! That's not a favor! What is a favor?
Me: It's something I asked you to do for me to help me.
Kai: If I go upstairs to get a diaper, will you give me a chocolate?
Me: Yes.
Kai: If I go upstairs and get a diaper, will you give me TWO chocolates?
Me: No, you asked for one chocolate, not two.
Kai: I didn't say ONE chocolate.
Me: You said A chocolate. A means ONE.