Billy Madison - Prime Numbers
Ok, I could be wrong, but in the scene where Billy re-enters his 3rd grade classroom after being in high school, right before he enters, the teacher is teaching prime numbers. Read what you can of the numbers on the blackboard before it cuts away. The numbers appear to read 1, 3, 5... etc. Now, if you know your math, you'll know that not only is 1 NOT a prime number, but 2 is, and should be in there. It might just be the 2 cut off by her, but I couldn't tell.
on 06-17-2001 and