CS 103, or "Mathematical Foundation of Computing," is the first theoretical computer science class most students take,and is taught by the computer science department.

CS 103 is required for a significant number of other courses in computer science. At the lowest level, CS 121, CS 143, CS 145, CS 154, CS 156, CS 157, and CS 161 all directly require CS 103. Many 200 series CS courses depend on these courses as prerequisites, and not all courses that depend on 103 are listed. Therefore, for a computer scientist at Stanford, experience with discrete mathematics is very important.