Determination of the day of the week the day of the week without any calculations. Examples: December is in row F and 26 is in column E, so the letter for the date is C located in row F and column E. 93 (year mod 100) is in row D (year row) and the letter C in the year row is located in column G. 18 ([year/100] in the Gregorian century column) is in row C (century row) and the letter in the century row and column G is B, so the day of the week is Tuesday. October 13 is a F day. The letter F
Determination of the day of the week example, that January 1995 is to be treated as month 13 of 1994. The formula for the Gregorian calendar is where The only difference is one between Zeller’s algorithm () and the Gaussian algorithm (), that is . So we can get the values of months from those for the Gaussian algorithm by adding one: In a partly tabular method by Schwerdtfeger, the year is split into the century and the two digit year within the century. The approach depends on the month. For , so is between 0 and 99. For , The formula for the day of the