Pi Approximation day is a similar holiday, celebrated on July 22 (from the approximation 22/7). <ref>[http://www.usatoday.com/tech/science/mathscience/2007-03-14-pi-day_N.htm USA Today (3/14/2007) - Pi-day]</ref> | Pi Approximation day is a similar holiday, celebrated on July 22 (from the approximation 22/7). <ref>[http://www.usatoday.com/tech/science/mathscience/2007-03-14-pi-day_N.htm USA Today (3/14/2007) - Pi-day]</ref> |