The poem humorously describes a student named Betty Sue who believes she scored a 9 out of 9 on her AP exam, but during the grading process her score is reduced multiple times by the chief reader Rosenstein for various errors, until she is ultimately given a score of 0 out of 9. The chief reader methodically goes through each of Betty Sue's mistakes on different problems, explaining how her score was reduced one point at a time for issues like using the wrong derivative, incorrect copying of numbers, improper set up of limits of integration, and inconsistent use of constants.