What is the most common word for a student with special duties who helps the teacher?
As I googled it, I found a number of suggestions including monitor, prefect and factotum. But which one is the most commonly used term in American and English schools?
Update: In an American movie set in an elementary school, one of the students introduces herself to a new teacher, beginning with the words "as the class factotum, I'd like to say 'welcome to our school'." Is "factotum" a common word for a student representative of his/her class?