Graffiti: What do two plus two equal?

A mathematician, an accountant and an economist apply for the same job.
The interviewe calls in the mathematician and asks “What do two plus two equal?”
The mathematician replies “Four”.
The interviewer asks “Four exactly?”
the mathematician looks at the interviewer incredulously and says “Yes, four, exactly.”

Then the interviewer calls in the accountant and asks the same question “What do two plus two equals?”
The accountant says “On aver-age, four – give or take ten percent, but on average four.”

Then the interviewer calls in the economist and posses the same question, “What do two plus two equal?”
The economist gets up, locks the door, closes the shade, sits down next to the interviewer and says
"What do you want it to equal?”