This is misleading and false when it comes to Course 18. Math classes numbering has much more structure. 18.XYZ where Z >= 5 are grad classes. X = 1 is An

This is misleading and false when it comes to Course 18. Math classes numbering has much more structure. 18.XYZ where Z >= 5 are grad classes. X = 1 is Analysis X = 2 is Mathematical Physics X = 3 is Applied Mathematics X = 4 is Theoretical Computer Science X = 5 is Logic X = 7 is Algebra X = 9 is Topology