Determination of the day of the week *104804 + 4, "n" = 104804 and "k" = 4 which implies that August 13, 2009 is the fourth day into the 104805th week since 01/01/0001. 13 August 2009 is Thursday; therefore, the first day of the week must be Monday, and it is concluded that the first day 01/01/0001 of the calendar is "Monday". Based on this, the remainder of the ratio "Base/7", defined above as "k", decides what day of the week it is. If "k" = 0, it's Monday, "k" = 1, it's Tuesday, etc. Determination of the day of the week The determination of the day
Determination of the day of the week where is the day of the week (counting upwards from 1 on Sunday instead of 0 in Gauss's version); and , , and are numbers depending on the day, month, century and year which are tabulated in the "Complete table: Julian and Gregorian calendars" above. Note that the numbers tabulated for y can also be described by the following equation: Where So, for example, if you want to find 'y' for the year 1987: In Zeller’s algorithm, the months are numbered from 3 for March to 14 for February. The year is assumed to begin in March; this means, for