Early on in the movie it is established that Mr. Lisbon teaches Math. And when Trip Fontaine goes to ask Mr. Lisbon if he can take the Lux to the homecoming dance, Mr. Lisbon replies, that it is fourth period, and he does not have Trip for math until fifth period. But in the part where Trip comes back from smoking marijuana in his car during 5th period, it says he goes into the wrong HISTORY class, not the wrong MATH class. How could they have messed that one up?