(A true story from my friend in the Army)
In this particular branch of the Army's officer training school, the instructor was returning a test. The students identified their work by the last four digits of their Social Security number. In the early hours of a morning, the instructor was calling the numbers.
"Four-seven-seven-zero?" he asked.
"Here," replied one half-awake lieutenant-to-be. Taking the paper, though,
he realized he had mistakenly asked for the wrong paper.
"Seven-zero-seven-five?" asked the instructor.
"Here," repeated the student, gearing for trouble.
"I thought you were four-seven-seven-zero, soldier," spoke the teacher.
"That's right, sir," answered our hero. "I have a nick-number."