You earn points by playing Math World. Please note that the points in Math World are not the same as in the competition. The points you see in the Hall of Fame ranking list are counted as an average of the points that the class has earned. The more active the students are, the more points they will earn.
Repeating the same activities over and over is not considered as being active and those points won't count towards the competition. The exact formula for the calculation of points is not disclosed in order to prevent cheating.