Maryland's university system is considering a plan to require all high-school students seeking admission to its universities to enroll in a fourth math course and take math as seniors. If approved, the changes could affect students who begin ninth grade in 2011. "Math is not a spectator sport," said Chancellor William E. Kirwan, a former math professor. "If you get away from it for a year, you lose a lot. The research is pretty clear and consistent that it makes a difference to have math your senior year."