If you insist that weeks begin on <SOME WEEKDAY>, then either some of the first week of a year is in the previous calendar year, or some days of the new year aren't in the first week.
365 mod 7 is not 0. Neither is 265.24 (leap years don't exist on century years).
If you insist that weeks begin on <SOME WEEKDAY>, then either some of the first week of a year is in the previous calendar year, or some days of the new year aren't in the first week.
365 mod 7 is not 0. Neither is 265.24 (leap years don't exist on century years).