Arithmetic Lesson is a 15-minute dramatic film that illustrates the courage of the human spirit for survival through the eyes of a seven-year-old Chinese American girl, Gracie. Gracie's mother, Mei, is comatose in the hospital. Gracie's father, Yong, hires an au pair from Taiwan, Ah San, to take care of Gracie. Ah San provides the daily care for Gracie, which includes overseeing Gracie as she does her homework and taking care of all domestic chores. Unknown to Yong, Ah San becomes impatient with the care-taking of Gracie and becomes abusive to the young child.
Throughout many events in the course of the film, Gracie finds the courage to tell her father that Ah San has hurt her physically, which results in the eviction of Ah San. Gracie learns to comfort herself instead of constantly seeking comforts from the emotionally unavailable adults around her.