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.
Show HN: How to mentally calculate the day of the week for any date
21–26 of 26 posts
Re: Show HN: How to mentally calculate the day of the week for any date
#22It'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)
Re: Show HN: How to mentally calculate the day of the week for any date
#23I 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.
Re: Show HN: How to mentally calculate the day of the week for any date
#24Decades 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.
Re: Show HN: How to mentally calculate the day of the week for any date
#25Oh my god that animation at the top keeps causing a layout shift on my 13 mini. Who thought that was a good idea?
Re: Show HN: How to mentally calculate the day of the week for any date
#26[flagged]
I know this is flagged, and I know the guidelines say not to complain about tangential annoyances, but the reason given is that "they're too common to be interesting" -- but is that true about LLM-written articles? A case could be made that it will only become more true if nobody objects.
I don't know what it is about LLM writing style, but I agree, it just triggers something in my brain and I can't get myself to read it.