Supposedly it takes 21 days to form a habit, whether good or bad. Students who received a second-quarter grade lower than a C in Mr. Paul's math class are eligible to put their names in a drawing. Whoever is randomly chosen will participate in “THE 21-DAY CHALLENGE.” If the student successfully completes his or her homework for 21 days in a row, Mr. Paul will pay him or her $21. If the student is not successful, another student will be chosen until someone is successful.