Continuity mistake: The flower earrings from Kat Valdez in the press conference are worn with the little petals on the inside; when she comes out of the press conference on the roof, the flower earrings are worn with the little petals on the outside. (00:39:33 - 00:42:28)
Character mistake: After the math club students, in unison, cited pi to 3.141592, Percy continued with "65839" - but only the "65" are correct. He should have said "65358..." before being cut off (or "65359" if he was rounding up the last "89793238"). Even though the movie is classified as a comedy, Percy was showing off, but he was wrong. Charlie, Math Club Advisor, also committed a mistake because he stopped Percy by saying "Percy, we got it. Good" (as though Percy was correct). (00:04:29)