What number are you calling?

What number are you calling?

an expression used when one suspects that a telephone caller may have gotten the wrong number. Bob (on the telephone): Hello? Mary: Hello, is Sally there? Bob: Uh, what number are you calling? Mary: I guess I have the wrong number. Sorry. Bob: No problem. Good-bye. When the receptionist asked, "What number are you calling?" I realized I had made a mistake.
See also: number