This study investigated college students'' knowledge of functions before and after instruction using the Rule of Three. The Rule of Three is the dictum that functions should be taught symbolically, graphically and numerically, and as many examples as possible should combine all three views. O''Callaghan (1998) and Markovits, Eylon, and Bruckheimer''s (1986) frameworks for examining components of the concept of function were used to investigate the students'' knowledge. Four students were chosen based on pretest scores, written responses, and scheduling conflicts. Data were collected from translating tasks, two interviews and two tests, and an ongoing comparative analysis was used (Glaser & Strauss, 1967). Initially, the students were tied to their calculators, used them extensively and the completion of any task usually depended on the students'' skill with the calculator. After instruction, the students were less reliant on technology and calculators were now used to confirm solutions acquired using a combination of procedures.