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  • >The trick = nearest squad date → leftover → walk from the Doomsday.

    When i do the 31/OCT, the solution show 10/10 as nearest squadday, i though 11/7 is the nearest ?

  • It's pretty bad form to give the doomsday algorithm and not give credit to John H. Conway who invented it. https://en.wikipedia.org/wiki/Doomsday_rule
  • Awesome site and guide, I just don't understand why all dates have the month in front of the date.

    Isn't this very confusing to anyone outside US?

    I get why it defaulted to this format, but in this day and age - it's trivial to automatically adjust it to the user's localization / preferences.

  • Decades ago, I was reading about tricks, or as it was put, a systematic approach to do arithmetics without a pen. Those were paid courses.

    It should have been obvious by then how irrelevant the whole thing was, since calculators with all kinds of shapes and forms were already widely available.

    When you look at this page, there is a fair amount of memorization needed to make it somewhat useful. Then you don't want to make any mistakes in any of the steps. And you want to make sure you still remember everything by the time you need to use it.

    That is a very roundabout way to say that I am fairly confident that nobody is actually going to "learn" what's in the page and apply it in realistic situations, and it's a complete waste of electricity to vibe code this page.

  • The difficult part, which is glanced over, is calculating the number of leap years for the year "slide" in Part 5.

    A bit more guidance there would go a long way.

    by eps
  • It's cool. Here a little different way to calculate. Day number + month number + year number, modulo 7 => weekday number. Year number this year is 3, goes +1 every year, +2 in leap year. Month numbers if not leap year: 033614625035. Day number is ordinary day of the month. 24th Dec 2026 would be: 24 + 5 + 3 = 32. 32 mod 7 is 4 (Thursday)
  • Cool site! When I do this trick I prefer using Bob Goddard's 'first Sunday' method [0]. It minimises the number of operations you need to do and makes it so you only need to keep track of one running total.

    [0] https://firstsundaydoomsday.blogspot.com/2009/12/quick-start...

  • I don't normally bother complaining about LLM writing, but this case is uncommonly bad. Everything above the fold is a nightmare. It's physically painful to see what's being done to English, my native language.

    It lacks so much human guidance that it starts to veer into nonsense: "Suspicious? Check those dates against a real calendar." This doesn't make sense in this context. Those dates are examples produced by a computer, not the result of a person actually doing the trick.

    I want to cry.

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