0.5 course from: Mathematics 2120A/B or 2211A/B, or the former 203b.0.5 course from: Calculus 2302A/B or 2502A/B.0.5 course from: Calculus 2303A/B or 2503A/B.2.5 additional courses from: Differential Equations 2402A, any Mathematics course at the 2000 level or above.