Eight-day week Eight-day week Some historical calendars had "weeks" of eight days. In the Burmese version of Theravada Buddhism, the week has eight days. Wednesday is divided into Wednesday proper (midnight to noon) and Rahu (noon to midnight). Each day is associated with a compass direction, a planet, and a totem animal. The ancient Etruscans developed an eight-day market week known as the nundinum around the 8th or 7th century BC. This was passed on to the Romans no later than the 6th century BC. As Rome expanded, it encountered the seven-day week and for a time attempted to include both. The
Determination of the day of the week his collected works in 1927. Gauss' method was applicable to the Gregorian calendar. He numbered the weekdays from 0 to 6 starting with Sunday. He defined the following operation: The weekday of 1 January in year number is where is the remainder after division of by , or modulo . This formula was also converted into graphical and tabular methods for calculating any day of the week by Kraitchik and Schwerdtfeger. Another variation of the above algorithm likewise works with no lookup tables. A slight disadvantage is the unusual month and year counting convention. The formula is where For example,