Continuity mistake: When Lisa is in Principal Skinner's office, there isn't a scoreboard control panel on the desk, yet when there is an overhead shot of his desk, one suddenly appears.
Revealing mistake: When Lisa is daydreaming about her failed test, the president of Harvard talks to her. When he says, "Nasty business that zero", his right white sleeve turns the same color as the glass above the door.
Continuity mistake: When Ralph comes to see Lisa, she is wearing her turquoise slippers. However, after he leaves and she drops the book on the floor, her slippers have gone.
Audio problem: Superintendent Chalmers' mouth doesn't move when he says "Idiot."
Audio problem: When Homer says "According to my driver's license, I weigh 140 pounds" his mouth is not in sync with his voice.
Revealing mistake: Two kids in the middle of the class do not have a test. However, they are shown writing on their desk as if they had a test paper.
Continuity mistake: When Lisa is getting the answers to her test, the coffee mug changes colors.
Revealing mistake: When Nelson is offering Lisa the fraction quiz answers, right before Lisa says she's never cheated before and won't again, her right hand disappears for a single frame.
