When Jerry is at the restaurant with his parents - his father tries to calculate a 12.4% tip on the "Wizard". The number turns out to be 4 dollarsw and 36.66666 cents. That is not possible unless the check was accurate to a fraction of a cent.

(The number that meets this calculation is between 35.21 or 35.22 - in fact, the correct answer is very close to 35.21505376344086021505376344086)