Level of the Course (First Digit)
The first digit of the course number indicates the level of the course: roughly,

1 and 2 indicate underclass courses;
 3 and 4, upper class courses;
 5, professionallevel and mathematics education courses;
 6 and 7, graduate courses.
Subject Matter (Second Digit)
Within the MATH subject area, the second digit often indicates the subject matter:

0, general;
 1 and 2, analysis;
 3 and 4, algebra and combinatorics;
 5 and 6, topology and geometry;

7, probability and statistics;

8, logic;

9, other.
Conversion From 3 to 4 Digits
In the MATH subject area, conversion of courses numbers from the old 3digit system to the new 4digit system was accomplished in most cases by adding a 0 as the 4th digit. Exceptions are as follows:

MATH 005 becomes 1005,
 MATH 006 becomes 1006,
 MATH 011 becomes 1011,
 MATH 012 becomes 1012,
 MATH 103 becomes 1300,
 MATH 105 becomes 1105,
 MATH 106 becomes 1106,
 MATH 109 becomes 1009.
Course numbers with 4 digits will be used from summer 2008 forward.