“Human calculators” are those rare individuals whose minds have a strange and remarkable ability with numbers. Oddly, many of them have been unable to master other fields of learning; some of them could not read or write. Yet, unlike the average person, some have matched or beaten the speed and accuracy of modern calculating machines! This article presents the stories of three famous math prodigies of the last three centuries: Jedidiah Buxton, Johann Dase, and Charles Cansler. Each of these men