William Shanks

William Shanks (/ˈʃæŋks/; 25 January 1812 – June 1882) was an English amateur mathematician. He is famous for his calculation of π to 707 decimal places in 1873, which was correct up to the first 527 places. The error was discovered in 1944 by D. F. Ferguson (using a mechanical desk calculator). Nevertheless, Shanks's approximation was the longest expansion of π until the advent of the digital electronic computer in the 1940s.