The word "JISM" that Mr Shoop writes and then erases on the blackboard, changes as to how much and where it was erased between shots.
At the beach, after Anna-Maria removes her shorts and top to reveal her bikini, she is shown in the background of a subsequent scene with her shorts and top still on.
When Rhonda begins her labor pains during the test, she breaks her pencil. Later when she tells Kevin that "it's starting" her pencil is still intact.
When Pam tells Freddy she wants to move in with him as her wish, and he goes to open the door to his apartment (with an armload of groceries), the door to his apartment is already ajar.
When Ms. Bishop first sees that Pam is staying at Mr. Shoop's place, it is obviously daylight. When Mr. Shoop followers her outside, and Robin warns Freddy about the emotional damage that situation could do to Pam, it is nighttime.
When the test scores were announced, the average was stated as 63. The average should be 65 if rounded up.
Larry - 55, Rhonda - 43, Eakian - 74, Denise - 38, Kevin - 75, Chainsaw - 59, Dave - 70, Pam - 82, Jerome - 91 = 583
If you divide 583 by 9 you get 64.778.
The Tongue Lips shirt didn't exist in 1969 and was no Rolling Stones 69 Farewell tour . The tongue lips Rolling Stones logo was designed by John Pasche in 1970.
It is mentioned that The Texas Chain Saw Massacre (1974) is a 1973 movie. It is in fact a 1974 movie.
When the class goes to the library, Alan Eakian is reading Dr. Seuss's "Horton Hears a Who." This would be a book geared for a grade school library, intended for no higher than a third grade reading level. That book would never be found in a high school library.
When Rhonda stands up during first roll call and pats her pregnant stomach, the echo of the ball under her shirt is audible.
When Chainsaw and Dave barge in to scare the potential substitute teacher, they are supposed to be running two chainsaws. Two-stroke chainsaws produce a lot of blueish exhaust smoke. There is no smoke visible in the shot.
Near the end of the movie, Chainsaw's dad says that he and his wife stopped having kids because of Chainsaw. However, in Chainsaw's dream the day before the test, he has a younger sister. The younger sister may have just existed in the dream or maybe the parents gave birth to the sister and due to Chainsaw's behavior when he was young that the parents decided to stop having kids.
When Freddy is bringing in groceries as Pam is waiting for him to ask if she can live there, there is an unwrapped roll of paper towels in one of the grocery bags.
When Mr. Shoop is trying to convince Wondermutt that Bob has come back by cutting a new doll's head off, he says, "Wondermutt, look, I found Bob!" as he holds up the head. All the while, his mouth is visible in the background and it does not move during the entire sentence.
At the end of the test, Dave is hurrying to finish and quietly announces his answers as he's filling them in. He says "C, C, C, C...." but fills in "C, D, C, D...."
In the first day of class, there are many more students who later do not appear in later lessons (not counting Jerome whose six-week absence was due to his "zipper [getting] stuck." They perhaps moved away, dropped out of high school or switched schools, but there is never a statement clearing this nor anyone seems to inquire about their later absence.
When Chainsaw's father is speaking to Gills, he tells him that because of Chainsaw, he and his wife stopped having kids, yet Chainsaw has a younger sister, as shown in his dream.
When Mr. Shoop tells Mr. Gills that the kids are as smart as you and me, and Mr. Gills corrects him, saying you and I; Mr. Gills is the one that's wrong. Mr. Shoop used the correct grammar. (It's possible this is on purpose, to emphasize that Gills is a pompous jerk.)
When Pam asks Freddy "French or Italian?" he says "French", but she grabs and starts shaking the Italian dressing.
"Chainsaw" refers to The Texas Chainsaw Massacre as a 1973 classic, but that movie came out in 1974.