William S. Hutchings
（重定向自Lightning Calculator）
William Street Hutchings, (January 7, 1832 - August 25, 1911) also known as Professor Hutchings and the Lightning Calculator, was a 19th-century math prodigy and mental calculator who P. T. Barnum first billed as the "Boy Lightning Calculator". He later worked as a sideshow barker and wrote a book called The Lightning Calculator.