Mathematics Throughout History

Math and Calendars in History

Can we change the calendars now in use?

The present calendar is an annual one, and changes every year, much to the happiness of calendar publishers. This is because 365-days-in-a-year is not evenly divisible by the number of days in the week: 365 / 7 = 52, with a remainder of 1 (or 52.142857…). This means that a given year usually begins and ends on the same weekday; and it also means that the next year bumps January 1 (and all following dates) to the next weekday, and a new calendar is born each year. But because the calendar we now have is so ingrained in everything we do, it is doubtful that there will be any changes soon.

Not that there haven’t been suggestions. One is called the World (or Worldsday) calendar, in which each date would always fall on the same day of the week, and all the holidays occur on the same day of the year. With this calendar, each year begins on Sunday, January 1 and each working year begins on Monday, January 2. The reason why the calendar is called “perpetual” or “perennial” is that the year ends with a 365th day following December 30, marked with a “W” for “Worldsday” (our current “December 31”). Leap years would still have to be added, probably at the end of June (some suggest a June 31 be added). Both extra days could act as world holidays.

The drawbacks? Besides the obvious—no one wanting to change an already entrenched system—the suspicious would revolt. After all, on the World Calendar, there are four Friday the 13ths.


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