The number of days in a year is 365 or 366, neither of which is divisible by 7. And not every week starts from scratch, there is a Monday every seven days, that is to say, the cycle is 7. Whether two days are the same week is only related to whether there is a multiple of 7, and it has nothing to do with whether it is the same day every year, so the annual 65438+1 October1may be any one from Monday to Sunday.