Abbott's toupee shifts noticeably during the "7 times 13 = 28" scene. (The "shift" is due to the fact that the scene was filmed after principal photography was completed. It was felt that at least one classic "routine" had to be inserted into the picture. You will notice that Lou is also heavier during this footage. Also filmed at this time was the routine with Sidney Fields, replacing a less confrontational sequence filmed with Eddy Waller.)