The first digit in course number designations denotes the year in which the course ordinarily is found in the curricular outlines or "checksheets," which are available from the major department or academic advisor. The second and third digits make the course number unique within a department. The fourth digit is 4 if the course is a one-term terminal course, 5 if the course is the first term in a sequence, and 6 if the second term in a sequence. As a general rule, courses with 0 as the first digit do not carry university credit. Agricultural Technology courses, however, are an exception. I believe that means if the course starts with: 1 = freshman 2 = sophomore 3 = junior 4 = senior 5 = graduate