When her mother was diagnosed with Alzheimer's disease, Catherine Landis set out to do something to protect her own brain. Hoping to avoid a similar fate, she went searching for brain exercises and landed on math. Considering herself innumerate, she was flustered by the mere word. Could she relearn it? Could this source of embarrassment become an opportunity? TWO TRAINS LEAVE THE STATION: A Meditation on Age, Alzheimer's, and Arithmetic, is the story of how Catherine relearned math while grappling with her mother's illness and her own inevitable aging.