Jerry says that in order to determine the winner of the football pool, take the difference in the scores and subtract multiples of 5, and the winning number would be in the range of 1-9 - in this case, 6. However, 6 through 9 could not be a winning number, as they would reduce to 1 through 4 respectively (so the winning number could only be in the range of 1-5 and his calculation was also in error).