I understand May 35 is sometimes used to refer to June 4, the date of Tiananmen Square protest. Mainland China sometimes censors June 4 so May 35 is used instead.
@@june012006 Well, it seems to be just an expression, rather than a full statement, so I wouldn't expect a semicolon for that even in C#. Then again, I think I'm wrong since C# uses the Random class and not Math.Random.
I used to use this trick to fool computers into using software licenses that should have expired. Put the computer clock back 28 (I think) years and the date will match from then onwards.
This was exactly how we avoided the y2k (whoever remembers that?!) problem on a number of systems. Since 2000 was awkwardly a leap year, we could just put the clock to 1972. 28 years rock. Kinda not entirely sure how that divides in 400 though :(
As said above, 28 years only works if you don't pass a year divisible by 100 (but not by 400). Because of those 3 years in the 400 year cycle it matches.
I clicked on this thinking we were going to talk about how many different kinds of calendar systems there are, and the different ways they work with all the little quirks and conversions. Three and a half minutes in I'm wondering if I've spent my whole life not noticing this underground world of trading old calendars for reuse in later years.
Hi Simon, Because I was born on Friday the thirteenth 1961, I began to look carefully at the calendar. In the encyclopedia(the internet of 1970) I found a perpetual calendar. After I studied that until I understood how it worked, I found a perpetual calendar on a brass disk that I carried around for about 10 years then lost it. I wanted to find a replacement, but since I knew the math so well, I thought I would make my own. I worked out that if you used the fingers of your left hand( I was already remembering other things on my right) you could count days of the week by making the least important day (Monday) your pinkie, your ring finger (think wedding) for Wednesday, your middle finger is what you tell your boss on Friday and the most important day is your index finger Sunday. The spaces in between are the remaining days. Then with your thumb you can count days, starting on one weekday, until you land on a finger or finger space that indicates the day of the week you're looking for. This idea can be extended to the entire calendar, with some other finger tricks.
@@standupmaths My bad it was my other account. Love your videos. Perhaps the first I watched was on calcucation of pi using a cardoboad circle. I myself am making some maths video by animating algebriac equations for high school kids. I feel there is a serious need and market to animate maths equations so that youngsters can learn them quickly. I am subscribing through this channel too.
From what I understand, handmade medieval calendars were designed to be reused every year. Instead of listing the day of the week for each date, the dates were labeled with letters from A through G, as a repeating cycle of seven letters. Then you would look in a table to find out what the "Dominical letter" (that is, "Sunday letter") was for the year you wished to know about. Leap years would have two letters, because of the interruption in February.
I think they’d be a _bit_ suspicious if I told my friend that they just woke up from a *500 year coma* and I’m still youthful as ever. Maybe if I told me that I was a robot replacement?
It was 11 days that went missing from the British calendar in 1752, not 13. If you have a UNIX-style OS you can actually see the calendar for that month by entering 'cal 9 1752' at the prompt.
You are such a positive person, it's a pleasure to watch your videos. And your English is so clear so it's completely understandable for those who's native is different like me. And of course topics you are talking about are always fun and interesting, but all that becomes obvious if you take a look on the number of likes under that video. One of them is mine.
I heard a looong time ago that looking through all the 400 calendar years until they loop around, the 13th day of each month is most frequent a Friday.
I was highly disappointed to discover that the calculators of 1974 calender was not real, I was so ready to go and buy it immediately. Please make this a real thing we can buy!!
This almost brought back memories for me. In the early to mid 1970s, there was a shop selling calculators at the top of the High Street in Guildford which I visited numerous times in summer holidays to try out and generally lust over the machines on sale there (all too expensive for my teenage budget).
I pre-ordered ages ago and forgotten about it. Feels like a present to myself. Now I can't wait again! Things you can make and do in the 4th dimension I also own a signed copy of, however I feel like I'm the only one massively excited about that :p Thanks matt :)
I also celebrate every 500 days with my girlfriend. This year I had my 2500 days together. My girlfriend found it great, but everybody also found it crazy, but then... they started calculating their own 500 days anniversary :D
the 823 was explored in Dave Gorman's book "Too Much information" where he tracked down the original source as I recall ^_^. I give the book 5 stars a must read for information nerds and it also contains a surprising move into badger-based glove puppetry.
hehe great I've got it on audio book (like most of my books ^_^) so unfortunately I couldn't just look up the exact bit and save you the money, I do think you'll enjoy it though ^_^
I love when you and your better (? :P ) half celebrate your anniversary! From the sound of it you two absolutely deserve each other (meant in the best way possible xD )! Love your videos Matt, as your mathematics comedy, keep up the good work! P.S.: I recently made the origami dodecahedron (funny, spelling thinks that's wrong and has no alternative word but "rhododendron") from just yellow Post-It notes and it's beautiful! Took me close to two hours though... Will be making the five colored one sometime :D !
I love calculating calendars, don't know why :) I've always weirdly dreamed of obtaining a set of 14 old calendars and using them forever. Fun additional fact: The weekday your birthday falls on is actually NOT equally distributed over time! In a 400 year period, my own birthday falls on a Friday, Sunday or Tuesday 58 times each, on a Wednesday or Thursday 57 times and on a Monday or Saturday only 56 times. That bias seems insignificant at first, but the interesting part is, it will never go away, I could turn 1,000,000 years old. If you take the limit over time to calculate the probability your birthday falls on a given day of the week, the answer will never be exactly 1/7 which everyone might guess.
The Hebrew (Jewish) calendar also has 14 possible year calendars. In general, the year can start on any of 4 days of the week (not Sunday, Wednesday, or Friday) and the months alternate between 30 and 29 days. This gives a total of 354 days, plus another 30 in a leap year (7/19 years) for a total of 384 days. The only variations are a day added in the second month (355/385 days) or a day removed in the third month (353/383 days). 6 possible year lengths starting on 4 possible days would be 24 calendars, but this is limited by the day of the week the _next_ year would start. (The rules are actually not that complicated. I'll share if there's enough interest.)
How come no one mentions the flaud in the design for the calculator calendar? Some months are spread out over 6 weeks. (30 days months that start on a Sunday and 31 days months that start on a Saturday or Sunday). As seen in the video where Matt points out his 2000 day anniversary, there is not enough room for the entire month. It ends on the 29th... I would love to have this calendar, but only if he can fix this. It should be a 7 by 6 grid with 42 days in a month. Speaking of 42... 0:)
This was a lucky day. There were uploads from my 2 favorite UA-camrs, Matt (who I actually merely number 2) and Destin of Smarter Every day (who is number 1). And go figure, Destin is actually doing a math video for once and Matt is pretending to talk about math, but he’s really just showing off his calendar collection. BTW, I am glad Matt finally used the word correctly when I saw him in Alabama last month. None of this “maths” nonsense. We call it math here in America.
3:00 You made that yourself? How surprising! I definitely didn't figure that out in the first ten seconds when I saw the QR code. In 1974 those were about as common as iPhones.
In 1974, in 10th grade, I bought a TI SR-11 calculator after the price fell to $110. It had a square, square root, reciprocal, and pi keys, plus scientific notation.
Recycling can suck it! Reusing for the win! 👍 38? Other than the hair, holding up really well. 👍 Those 80's calendars are indeed rad. They'll tumble for ya and rock you like a hurricane.
Amazingly, year difference from Gregorian to Buddhist is 543. Easy enough to remember. Now to be fully exact, in Laos PDR, the year would change some time in April because Buddhist new year is around mid April.
Minor correction: when the UK switched to the Gregorian calendar in 1752 the discrepancy with the Julian calendar was 11 days, not 13. The discrepancy is 13 days *now*.
Because Matt's British, and only America has Pi Day (3-14). In the rest of the world that date is 14-3, and since neither the 3rd day of the 14th month or the 31st day of the 4th month are possible...
1:32 Waiting for the proof (prob. by example) that both leap-years and non-leap-years can start on any of the 7 days of the week. Otherwise, for all we know, some of these combinations might not be "possible". :-)
Matt, what is the best length of a week, month and year? I would think that the current year length is fine because of the seasons, but who cares about the moon cycle (doesn't even align well) and 7-day weeks? Having the same day of the week for each day of the month would be nice though (March 3rd is a thursday? October 3rd is a thursday!) Talking about October, I think the names of the months and weeks should be less... historic. SEPTember, OCTober, NOVember and DECember are already trying very hard, but are two months late. And the only ones to fit the system. And we should consider that quarters (which businesses deem necessary) fit exactly with the number of days/weeks/months. My thought was a 6-day week, 5-week months, 12 month-years, quarterly 'season' days, a 'year' day and a (possible) 'leap' day would not stray too far away from the current setup. It'd be nice if someone did some research into how many days a week should contain and how many of those should be worked for how many hours to achieve optimal productivity. Also I think we should consider that not every date should always occur on the same day because of birthdays: how sad would it be for someone to always have their birthday on a wednesday while others get a saturday?
The French tried this after the revolution, for about 12 years: en.wikipedia.org/wiki/French_Republican_calendar "There were twelve months, each divided into three ten-day weeks called décades. The tenth day, décadi, replaced Sunday as the day of rest and festivity. The five or six extra days needed to approximate the solar or tropical year were placed after the months at the end of each year and called complementary days." "The Republican calendar year began the day the autumnal equinox occurred in Paris, and had twelve months of 30 days each, which were given new names based on nature, principally having to do with the prevailing weather in and around Paris. For a short time, this even included decimal time: "Each day in the Republican Calendar was divided into ten hours, each hour into 100 decimal minutes, and each decimal minute into 100 decimal seconds. Thus an hour was 144 conventional minutes (more than twice as long as a conventional hour), a minute was 86.4 conventional seconds (44% longer than a conventional minute), and a second was 0.864 conventional seconds (13.6% shorter than a conventional second). "
The moon cycle is almost as important as the solar cycle At least for people living on shores since the relative position of the sun and moon give the time and height of tides.
@@christianbarnay2499 Sure it's important for those aspects, but not for the amount of days in a month, which was what I was getting it. Sorry for being unclear!
@@foogoid8682 That's really interesting! The Wiki doesn't show why Napoleon got rid of the calendar unfortunately, I'll look into that. I'm not a big fan of decimal systems at all though because of the number of divisors 10 has as compared to 12. As a matter of fact, I think we should adapt everything to a duodecimal system, but that's a whole other point!
Ultimately, there will be a use for a 15th calendar. Through the use of continued fractions, it can be shown that you want the year 5000 A.D. to have February 29 and 30.
@@alexkuusk The months don't make sense even for Christians. Come to think of it I don't actually think that the month names have religious significance. Of course days and months also have different names in different languages.
Yes, I was bit off about religion. Months are named after Roman emperors and gods, and ... numbers. Still, makes no sence for most people today. First month should be called "first month' and eight month should not be called tenth month (oct..).
You say you can't sell it. But can't you put the PDF or equivalent online? For free. You wouldn't be selling it. Though you wouldn't get money. I wouldn't judge you if you didn't want to share it for free.
Actually,december will have 5 saturdays, 5 sundays and 5 mondays in a pattern of 5-6-11-6 years (except when a year multiple of 100 but not 400 is involved in the gap,in which case we'd add one year to the gap)
I will share this video every time someone posts one of those stupid ridiculous aneurysm causing posts where they say "This month has 4 fridays this only happens every 395 years." or similar. Because every time I see someone post one of those posts I lose brain cells. Thank you for this video.
lol. Well, I can think of a few more letters one can use. θ, Δ, ζ... Ψομε τ- Damn you winspace... Come to think of it, all 24 are used, some more rare than others
I was hoping for a chart in excel of which of the 14 calendars are most useful. Which ones get used the most often in one 400-year cycle? Is one of the seven leap-year calendars particularly rare?
It wasn’t really a question. I think the moon phase has to practically break the idea of using a previous calendar, because the lunar cycle doesn’t align with our measurement of time in any way. The complete cycle is 29.53 days or so, but I think that changes, and also that the real value has a lot more than two decimal digits precision.
The lunar cycle is anything but random. It’s entirely predictable. There are Moon phase calculators. Calendars mark the day of a Moon phase, not the time, so there might be a bit of give there, in terms of finding another one. You’d likely just have to find the same phase at the beginning of a year for it to be correct, but I don’t know that it exists in recent enough history to have a printed calendar.
you should do a talk on the Eastmann calender of Eastmann Kodak fame. the year had 13 months each with 28 days = 364 the extra day was to be called world day or day zero the date would always land the day of the week. zero day would not have a day of the week.
So, in a leap year, would there also be a Day 00 (Double Zero), or "Leap Day" to keep things from falling out of sync without messing up the weekday cycle?
What about first day of the week? I think that counts as a different calendar, if you have 2019 calendar with Sunday as first day of week, or Monday as first day of week.
How does the lunar cycle affect repeatability? What I mean by that is how often is something like the full moon on a given day? How would I go about figuring that out math wise?
The Moon is crazy. Its orbit isn't circular, it's eccentric, about 5½%. And that eccentricity changes, up & down, over the course of months & years. The perigee-apogee line (line of apsides) revolves in about 8.8 years. Its orbit is tilted, and the orbital plane wobbles around in 18.6 years. Its orbital period (sidereal month) changes back and forth, somewhat erratically, from month to month, averaging 27.32166 days. The synodic month (that is, the cycle of phases, New Moon to New Moon), is on average, 29.530589 days, but that can vary substantially from month to month. Nothing is simple about the Moon. However, there is a thing called the Metonic cycle (named for Meton), that has the synodic month occurring 235 times in almost exactly 19 years. So there's a very-near repetition of Moon phases every 19 calendar years. Fred
Non leap years actually repeat every 5th or 6th year, depending on how many leap years are in, or every 11 years, so you don't have to go 400 years to see a single year repeat. Leap years repeat something like every 32 years.
I have every possible calendar configuration, the 14 mentioned, memorized. I can identify which one of the 14 any year is instantly and therefore I always know what day of the week any date was or will be. I also know the date and how many and which months any statistic falls on such as Thanksgiving Day or Friday the 13th. Any information such as whether or not there are 4 or 5 Mondays in a given month I can quickly mentally determine as well. I am a human calendar. I also invented a way to calculate any julian day of the week for any date as well as a homebrew formula I invented for both julian and Gregorian bc dates as well!
*_[_**_03:45_**_] "...is as far as..." yes-but what does that have to do with calendars that cycle over seven days and have a 100-year-no-leap step but do-have a 400-year-yes-leap step... it's just not information, saying, one is as far as the other is the other way..._* *_...also you've left-out the Greek 400-900 stepper, as well as the Nippur-Jewish calendar..._*
I like the Shire calendar. 2 variants, regular and leap year, makes good Hobbit sense. Of course, the 5-6 days that aren't part of a week or month would take some getting used to.
Wait wait wait. I've done some research on the Chinese Lunisolar calendar lately. How long does it take THAT thing to repeat -- Year, months, leap months, etc? That's gotta be one helluva mess.
That is a calendar of calculators from 1974. Not a 1974 calendar. It's just like a puppies calendar, only for nerds who are allergic to puppies, so their moms got them a calculator instead.
I had once read that the big scare that people had about Mayan calendar lining up with the year 2012 was an error because they forgot to add in all of the leap days since the first implemented Leap days. So, the end of the world on the Mayan calendar would have been sooner than the date we first believed.
I love the negative days. But I wouldn't bother with day 0. For culture reasons. Also, I ought to send you my unit converter at some point. It's not a traditional calculator, but I think it's cool.
"Which date is it?"
Matt: Let me see...its the -3rd of May!
that's one Parkercalender
it's*
Parker Calendar*
Jorge C. M. I‘m so sorry. I’m from Germany and learned English only in school. Thanks for your corrections!
Poland *
I understand May 35 is sometimes used to refer to June 4, the date of Tiananmen Square protest. Mainland China sometimes censors June 4 so May 35 is used instead.
Bring back Calculator Reviews on Numberphile!!!!
Yeah my subscription to South Surrey and Associated Regions Calculator Appreciation Society for Professionals and Amateurs has been way over due
Yes, why am I paying for my SSaARCASfPaA monthly subscription if not to get calculator reviews? BTW, this comment has already 2^8-1 likes!
@@GRBtutorials Not a Mersenne Prime :(
I was missled by the thumbnail to think it was another glorious calculator unboxing
0:16 how many time can one video mislead me , my heart can only take so much
I think 823 came from Math.Round(Math.Random() * 1000)
The "R" in "random" and in "round" are not capitalized though
@@eduardofreire8609 Maybe it's written in C#.
Can't be c#, no semi colon.
@@june012006 Well, it seems to be just an expression, rather than a full statement, so I wouldn't expect a semicolon for that even in C#. Then again, I think I'm wrong since C# uses the Random class and not Math.Random.
@@june012006 you're mixing up c++ and c#.
Either way, System.Math in c# indeed doesn't have Random method.
You do realize that you will have to start selling the calculator calender on your homepage now, don't you?
They are Parker calendars though. But I don't think people will mind
@@16m49x3, I think that's a great part of the charm, actually. ;)
A calculendar.
lol
... Did your wife say "we can celebrate every 500 days if that makes you remember it"?
Is it funny that this was my thought as well?
Seriously what's so special about 500? 499 would be prime at least!
@@SebBrosig But multiples of 499 would not be special, since they cannot be primes.
Actually pretty good excuse to always have pre-calculating and writing down the exact date that you cannot make yourself remembering.
I used to use this trick to fool computers into using software licenses that should have expired. Put the computer clock back 28 (I think) years and the date will match from then onwards.
On the condition you haven't gone over a multiple of 100 (but not 400)
You'd be hard-pressed to find someone who doesn't fulfill that condition.
This was exactly how we avoided the y2k (whoever remembers that?!) problem on a number of systems. Since 2000 was awkwardly a leap year, we could just put the clock to 1972. 28 years rock. Kinda not entirely sure how that divides in 400 though :(
As said above, 28 years only works if you don't pass a year divisible by 100 (but not by 400). Because of those 3 years in the 400 year cycle it matches.
Kenneth Ord yep. The calendars repeat every 28 years
I clicked on this thinking we were going to talk about how many different kinds of calendar systems there are, and the different ways they work with all the little quirks and conversions. Three and a half minutes in I'm wondering if I've spent my whole life not noticing this underground world of trading old calendars for reuse in later years.
Hi Simon, Because I was born on Friday the thirteenth 1961, I began to look carefully at the calendar. In the encyclopedia(the internet of 1970) I found a perpetual calendar. After I studied that until I understood how it worked, I found a perpetual calendar on a brass disk that I carried around for about 10 years then lost it. I wanted to find a replacement, but since I knew the math so well, I thought I would make my own. I worked out that if you used the fingers of your left hand( I was already remembering other things on my right) you could count days of the week by making the least important day (Monday) your pinkie, your ring finger (think wedding) for Wednesday, your middle finger is what you tell your boss on Friday and the most important day is your index finger Sunday. The spaces in between are the remaining days. Then with your thumb you can count days, starting on one weekday, until you land on a finger or finger space that indicates the day of the week you're looking for. This idea can be extended to the entire calendar, with some other finger tricks.
Wow! You're still alive. Good to see you. I subscribed to you in 2015 but somehow youtube forgets to notify me.
We are all at the mercy of the youtube subscriptions reminder algorithm!
@@standupmaths My bad it was my other account. Love your videos. Perhaps the first I watched was on calcucation of pi using a cardoboad circle. I myself am making some maths video by animating algebriac equations for high school kids. I feel there is a serious need and market to animate maths equations so that youngsters can learn them quickly. I am subscribing through this channel too.
From what I understand, handmade medieval calendars were designed to be reused every year.
Instead of listing the day of the week for each date, the dates were labeled with letters from A through G, as a repeating cycle of seven letters. Then you would look in a table to find out what the "Dominical letter" (that is, "Sunday letter") was for the year you wished to know about. Leap years would have two letters, because of the interruption in February.
I think they’d be a _bit_ suspicious if I told my friend that they just woke up from a *500 year coma* and I’m still youthful as ever. Maybe if I told me that I was a robot replacement?
Tell them you (and the room they're in) is a holographic simulation that was created to make them feel a bit more at ease when they woke up.
You’re going to need to hire some actors.
+standupmaths It’ll be like the start of Mission: Impossible - Fallout!
Fill his room with jungle plants and hang a model of Wheatley from the ceiling.
Tell them you've been eating lichen.
Take a friends mobile change the calendar settings and convince them they just woke up from coma, lollz
It was 11 days that went missing from the British calendar in 1752, not 13.
If you have a UNIX-style OS you can actually see the calendar for that month by entering 'cal 9 1752' at the prompt.
Whoops! Thanks. Added to the corrections.
Amazing! Thanks for this tip! :)
@@rageagainstthebath Glad to help :)
@@standupmaths My pleasure. From now on, I might call it 'The Parker Month'.
A Parker gap. See also: the Parker countdown for holy hand grenades.
@07:38 & @07:45 Years*
h9kh9k yeah I was confused thinking I heard wrong before but then he switch back and forth again...
Bumping this, nearly posted this myself
Something something Parker Square
Rise my friend, rise to the top of comments and conquer confusion.
Matt was also scrolling through his calender, but in March, he didn't notice he missed a day. the days count from -4 up to 30,while March has 31 days
You are such a positive person, it's a pleasure to watch your videos. And your English is so clear so it's completely understandable for those who's native is different like me. And of course topics you are talking about are always fun and interesting, but all that becomes obvious if you take a look on the number of likes under that video. One of them is mine.
4:08 made me wonder what to do with months where days spreads over to 6 different weeks, but 8:45 answered my question :-)
I heard a looong time ago that looking through all the 400 calendar years until they loop around, the 13th day of each month is most frequent a Friday.
I was highly disappointed to discover that the calculators of 1974 calender was not real, I was so ready to go and buy it immediately. Please make this a real thing we can buy!!
I misread this as how many calculators there are and got far to excited.
Matt, you are awesome and very entertaining!
The calendar will repeat itself every 28 years unless there is 8 years between 2 leap years
This almost brought back memories for me. In the early to mid 1970s, there was a shop selling calculators at the top of the High Street in Guildford which I visited numerous times in summer holidays to try out and generally lust over the machines on sale there (all too expensive for my teenage budget).
Looks like those memories were successfully retrieved after all.
@@dirm12 You're right. I guess I was hoping to wallow in nostalgia... and the calendar would've helped with that. :)
4:30 Ah! A Sumlock Anita 811 - A British-made early handheld calculator with early LED display. Possibly as early as 1972!
I pre-ordered ages ago and forgotten about it. Feels like a present to myself. Now I can't wait again! Things you can make and do in the 4th dimension I also own a signed copy of, however I feel like I'm the only one massively excited about that :p Thanks matt :)
Exactly what my dad did, he kept calendars and now he'll use old ones; it drives my wife NUTS!
hey! i can get that book for my birthday! it comes out the day before :) Good job Matt, love your vids!
I used to have my favorite 14 calenders that I cycled trough but the were unfortunatele left in my old apartment when I moved last time.
7:35 - "400 days" shouldn't that be 400 years? -- EDIT: Yep, see description.
EDIT2: Another error: In the description "reform" is typo'd as "refor".
I also celebrate every 500 days with my girlfriend. This year I had my 2500 days together. My girlfriend found it great, but everybody also found it crazy, but then... they started calculating their own 500 days anniversary :D
8:46 _"Because that makes more sense",_ sure... He genuinely got to buy anniversary presents 27% less often, what a chad.
I like the Kurzgesagt calendar.
Servus from this Bavarian Channel :)
@Adam Filinovich And PF 12019!
It's called the holocene calendar
As the difference between 2019 and 12019 is 25 gregorian cycles, they should be interchangeable indeed.
Is there anyone who doesn't? I know most people are indifferent, but is there anyone that's like "no, actually the Holocene calendar is garbage"?
the 823 was explored in Dave Gorman's book "Too Much information" where he tracked down the original source as I recall ^_^. I give the book 5 stars a must read for information nerds and it also contains a surprising move into badger-based glove puppetry.
I haven’t read it! Have ordered a copy.
hehe great I've got it on audio book (like most of my books ^_^) so unfortunately I couldn't just look up the exact bit and save you the money, I do think you'll enjoy it though ^_^
I love when you and your better (? :P ) half celebrate your anniversary!
From the sound of it you two absolutely deserve each other (meant in the best way possible xD )!
Love your videos Matt, as your mathematics comedy, keep up the good work!
P.S.: I recently made the origami dodecahedron (funny, spelling thinks that's wrong and has no alternative word but "rhododendron") from just yellow Post-It notes and it's beautiful! Took me close to two hours though... Will be making the five colored one sometime :D !
Too bad you can't sell that calendar. First thing I did after seeing it was look in the description for a link. Looking forward to the new book!
I had the same expression when it became apparent the calculator calendar wasn't real, but then it is real, it is made. Make it downloadable!
Already I found an eBay listing for a 1985 calendar saying "Vintage calendar with dates matching 2019, so can be used for that year!"
Is Matt already selling his calendars
1:30 Is this the updated Wadsworth's constant? (90 sec / 665 sec = 13.53%)
I love how nobody would think about this besides Matt.
After the correction where someone spotted a typo, you made another typo. You forgot the 'm' in 'reform'. Loved the video, keep up the good work!
I love calculating calendars, don't know why :) I've always weirdly dreamed of obtaining a set of 14 old calendars and using them forever.
Fun additional fact: The weekday your birthday falls on is actually NOT equally distributed over time!
In a 400 year period, my own birthday falls on a Friday, Sunday or Tuesday 58 times each, on a Wednesday or Thursday 57 times and on a Monday or Saturday only 56 times. That bias seems insignificant at first, but the interesting part is, it will never go away, I could turn 1,000,000 years old. If you take the limit over time to calculate the probability your birthday falls on a given day of the week, the answer will never be exactly 1/7 which everyone might guess.
I love Matt’s next level nerdity. 🤣
8:54 Is that a Parker Calendar? December only has 29 days
"The other problem with 2020" - yeah there's a lot of problems with 2020...
I recently got Things to Make and Do in the Fourth Dimension for my birthday, and I'm getting a collection of FOTSN DVDs for Christmas.
The Hebrew (Jewish) calendar also has 14 possible year calendars. In general, the year can start on any of 4 days of the week (not Sunday, Wednesday, or Friday) and the months alternate between 30 and 29 days. This gives a total of 354 days, plus another 30 in a leap year (7/19 years) for a total of 384 days. The only variations are a day added in the second month (355/385 days) or a day removed in the third month (353/383 days).
6 possible year lengths starting on 4 possible days would be 24 calendars, but this is limited by the day of the week the _next_ year would start.
(The rules are actually not that complicated. I'll share if there's enough interest.)
How come no one mentions the flaud in the design for the calculator calendar? Some months are spread out over 6 weeks. (30 days months that start on a Sunday and 31 days months that start on a Saturday or Sunday). As seen in the video where Matt points out his 2000 day anniversary, there is not enough room for the entire month. It ends on the 29th...
I would love to have this calendar, but only if he can fix this. It should be a 7 by 6 grid with 42 days in a month. Speaking of 42... 0:)
Thank you! have been scrolling way too long for this comment
This was a lucky day. There were uploads from my 2 favorite UA-camrs, Matt (who I actually merely number 2) and Destin of Smarter Every day (who is number 1). And go figure, Destin is actually doing a math video for once and Matt is pretending to talk about math, but he’s really just showing off his calendar collection.
BTW, I am glad Matt finally used the word correctly when I saw him in Alabama last month. None of this “maths” nonsense. We call it math here in America.
3:00 You made that yourself? How surprising! I definitely didn't figure that out in the first ten seconds when I saw the QR code. In 1974 those were about as common as iPhones.
Culture Club calendar. Still giggling at it decades later.
In 1974, in 10th grade, I bought a TI SR-11 calculator after the price fell to $110. It had a square, square root, reciprocal, and pi keys, plus scientific notation.
Recycling can suck it! Reusing for the win! 👍
38? Other than the hair, holding up really well. 👍
Those 80's calendars are indeed rad. They'll tumble for ya and rock you like a hurricane.
9:24 Of course I will have an (unneccessarily) nerdy new year. Many people will, as New Horizons will fly past Ultima Thule!
Amazingly, year difference from Gregorian to Buddhist is 543. Easy enough to remember. Now to be fully exact, in Laos PDR, the year would change some time in April because Buddhist new year is around mid April.
4:31 i can sort of deal with April "having" 35 days. But May "has" only 30? need a better calculator!~
Minor correction: when the UK switched to the Gregorian calendar in 1752 the discrepancy with the Julian calendar was 11 days, not 13. The discrepancy is 13 days *now*.
I like the jab at amazon
Why not wait a week and release the book on 3-14
Because Matt's British, and only America has Pi Day (3-14). In the rest of the world that date is 14-3, and since neither the 3rd day of the 14th month or the 31st day of the 4th month are possible...
@@bob_._. he's Australian, and since neither exist in that way why not make it come out on the day it works in another system
Also, it's never stopped him from celebrating pi day before, since he's made plenty of pi day videos
Just release it on May 1st then.
@@bob_._. May 1st could work with how he designed that calender. It just depends what day April starts on.
1:32 Waiting for the proof (prob. by example) that both leap-years and non-leap-years can start on any of the 7 days of the week. Otherwise, for all we know, some of these combinations might not be "possible". :-)
Matt, what is the best length of a week, month and year?
I would think that the current year length is fine because of the seasons, but who cares about the moon cycle (doesn't even align well) and 7-day weeks? Having the same day of the week for each day of the month would be nice though (March 3rd is a thursday? October 3rd is a thursday!) Talking about October, I think the names of the months and weeks should be less... historic. SEPTember, OCTober, NOVember and DECember are already trying very hard, but are two months late. And the only ones to fit the system. And we should consider that quarters (which businesses deem necessary) fit exactly with the number of days/weeks/months.
My thought was a 6-day week, 5-week months, 12 month-years, quarterly 'season' days, a 'year' day and a (possible) 'leap' day would not stray too far away from the current setup. It'd be nice if someone did some research into how many days a week should contain and how many of those should be worked for how many hours to achieve optimal productivity.
Also I think we should consider that not every date should always occur on the same day because of birthdays: how sad would it be for someone to always have their birthday on a wednesday while others get a saturday?
The French tried this after the revolution, for about 12 years: en.wikipedia.org/wiki/French_Republican_calendar
"There were twelve months, each divided into three ten-day weeks called décades. The tenth day, décadi, replaced Sunday as the day of rest and festivity. The five or six extra days needed to approximate the solar or tropical year were placed after the months at the end of each year and called complementary days."
"The Republican calendar year began the day the autumnal equinox occurred in Paris, and had twelve months of 30 days each, which were given new names based on nature, principally having to do with the prevailing weather in and around Paris.
For a short time, this even included decimal time:
"Each day in the Republican Calendar was divided into ten hours, each hour into 100 decimal minutes, and each decimal minute into 100 decimal seconds. Thus an hour was 144 conventional minutes (more than twice as long as a conventional hour), a minute was 86.4 conventional seconds (44% longer than a conventional minute), and a second was 0.864 conventional seconds (13.6% shorter than a conventional second). "
The moon cycle is almost as important as the solar cycle At least for people living on shores since the relative position of the sun and moon give the time and height of tides.
@@christianbarnay2499 Sure it's important for those aspects, but not for the amount of days in a month, which was what I was getting it. Sorry for being unclear!
@@foogoid8682 That's really interesting! The Wiki doesn't show why Napoleon got rid of the calendar unfortunately, I'll look into that.
I'm not a big fan of decimal systems at all though because of the number of divisors 10 has as compared to 12. As a matter of fact, I think we should adapt everything to a duodecimal system, but that's a whole other point!
Ultimately, there will be a use for a 15th calendar. Through the use of continued fractions, it can be shown that you want the year 5000 A.D. to have February 29 and 30.
I like the international fixed calendar. Except that weeks start on a Sunday in that calendar, which is just wrong. 😉
Yes, this is almost perfect calendar. Months should also be totally renamed, because they do not make sence for non christianic countries.
@@alexkuusk The months don't make sense even for Christians. Come to think of it I don't actually think that the month names have religious significance. Of course days and months also have different names in different languages.
Yes, I was bit off about religion. Months are named after Roman emperors and gods, and ... numbers. Still, makes no sence for most people today. First month should be called "first month' and eight month should not be called tenth month (oct..).
You say you can't sell it. But can't you put the PDF or equivalent online? For free. You wouldn't be selling it. Though you wouldn't get money. I wouldn't judge you if you didn't want to share it for free.
There might be a copyright issue with the pictures...
when will you do next calculator unboxing?
Arithmometer for example
Actually,december will have 5 saturdays, 5 sundays and 5 mondays in a pattern of 5-6-11-6 years (except when a year multiple of 100 but not 400 is involved in the gap,in which case we'd add one year to the gap)
Do you plan to sell the calculator calendar ? I would love to have one !
He said he won't
I will share this video every time someone posts one of those stupid ridiculous aneurysm causing posts where they say "This month has 4 fridays this only happens every 395 years." or similar. Because every time I see someone post one of those posts I lose brain cells. Thank you for this video.
There is only one calendar in base 146097, it just takes a while to print out though.
4:02 So... A Parker-calendar ?
I read the title as "how many calculators are there" somehow but was still not disappointed
boi im sure hes got that greek keyboard installed for the πurpose of using exactly one (1) letter
or perhaps anoτher one, in rare cases
Vennom Scandi not so rare when you write mathematical stuff
lol. Well, I can think of a few more letters one can use. θ, Δ, ζ... Ψομε τ- Damn you winspace... Come to think of it, all 24 are used, some more rare than others
The only ones I don't remember having used through my engineering course are: ι, ο, and υ. And only because of their similarity to roman letters.
7:36 - Are those Parker days?
I was hoping for a chart in excel of which of the 14 calendars are most useful. Which ones get used the most often in one 400-year cycle? Is one of the seven leap-year calendars particularly rare?
A lot of these wall calendars have Moon phase symbols too.
That's a good question, how many calendars would you need to make the moon phases correct?
It wasn’t really a question. I think the moon phase has to practically break the idea of using a previous calendar, because the lunar cycle doesn’t align with our measurement of time in any way. The complete cycle is 29.53 days or so, but I think that changes, and also that the real value has a lot more than two decimal digits precision.
we cant account for those, because moon cycles are random
@@BrekMartin so that would put us back to a new calendar every year... How boring
The lunar cycle is anything but random. It’s entirely predictable. There are Moon phase calculators. Calendars mark the day of a Moon phase, not the time, so there might be a bit of give there, in terms of finding another one. You’d likely just have to find the same phase at the beginning of a year for it to be correct, but I don’t know that it exists in recent enough history to have a printed calendar.
you should do a talk on the Eastmann calender of Eastmann Kodak fame. the year had 13 months each with 28 days = 364 the extra day was to be called world day or day zero the date would always land the day of the week. zero day would not have a day of the week.
So, in a leap year, would there also be a Day 00 (Double Zero), or "Leap Day" to keep things from falling out of sync without messing up the weekday cycle?
@@HeavyMetalMouse yes i think so ill check that and get back
I'm already looking forward to hindsight year!
What about first day of the week? I think that counts as a different calendar, if you have 2019 calendar with Sunday as first day of week, or Monday as first day of week.
How does the lunar cycle affect repeatability? What I mean by that is how often is something like the full moon on a given day? How would I go about figuring that out math wise?
The Moon is crazy. Its orbit isn't circular, it's eccentric, about 5½%.
And that eccentricity changes, up & down, over the course of months & years.
The perigee-apogee line (line of apsides) revolves in about 8.8 years.
Its orbit is tilted, and the orbital plane wobbles around in 18.6 years.
Its orbital period (sidereal month) changes back and forth, somewhat erratically, from month to month, averaging 27.32166 days.
The synodic month (that is, the cycle of phases, New Moon to New Moon), is on average, 29.530589 days, but that can vary substantially from month to month.
Nothing is simple about the Moon.
However, there is a thing called the Metonic cycle (named for Meton), that has the synodic month occurring 235 times in almost exactly 19 years.
So there's a very-near repetition of Moon phases every 19 calendar years.
Fred
Non leap years actually repeat every 5th or 6th year, depending on how many leap years are in, or every 11 years, so you don't have to go 400 years to see a single year repeat. Leap years repeat something like every 32 years.
Wow, with the way the days aren't right on that 1974 calculator calendar, it's kind of a Parker Calendar
Do a video on HP RPN calculators
I have every possible calendar configuration, the 14 mentioned, memorized. I can identify which one of the 14 any year is instantly and therefore I always know what day of the week any date was or will be. I also know the date and how many and which months any statistic falls on such as Thanksgiving Day or Friday the 13th. Any information such as whether or not there are 4 or 5 Mondays in a given month I can quickly mentally determine as well. I am a human calendar. I also invented a way to calculate any julian day of the week for any date as well as a homebrew formula I invented for both julian and Gregorian bc dates as well!
I take about 2 seconds or less to calculate any date.
Surprised not to see anyone else mentioning, but I enjoy that book title :)
*_[_**_03:45_**_] "...is as far as..." yes-but what does that have to do with calendars that cycle over seven days and have a 100-year-no-leap step but do-have a 400-year-yes-leap step... it's just not information, saying, one is as far as the other is the other way..._*
*_...also you've left-out the Greek 400-900 stepper, as well as the Nippur-Jewish calendar..._*
I like the Shire calendar. 2 variants, regular and leap year, makes good Hobbit sense. Of course, the 5-6 days that aren't part of a week or month would take some getting used to.
Wait wait wait. I've done some research on the Chinese Lunisolar calendar lately. How long does it take THAT thing to repeat -- Year, months, leap months, etc? That's gotta be one helluva mess.
In microsoft excel the 29th of February 1900 (wrongly) exists
You put QR codes on your 1974 calendar? :(
That is a calendar of calculators from 1974. Not a 1974 calendar. It's just like a puppies calendar, only for nerds who are allergic to puppies, so their moms got them a calculator instead.
Each one gives more facts about that calculator. It is technically a 2019 calendar about 1974.
Great Scott! Oh wait, that was like ten years later.
@@standupmaths I tried to scan one, but my screen is too low res.
Well I guess I can use my 2011 calendar I got as a gift (and didn't use much) again in about 3 years
I had once read that the big scare that people had about Mayan calendar lining up with the year 2012 was an error because they forgot to add in all of the leap days since the first implemented Leap days. So, the end of the world on the Mayan calendar would have been sooner than the date we first believed.
Really thank you - you made my day ... 400 unique but still ....
Only Matt Parker would abbreviate to Wednes and Satur
As soon as I saw the title, I said 14 then wanted to watch the vid to make sure I wasn't insane
Claire says thank you for a nice 6000th day since launch.
If you could redesign the calendar system, what would you do?
Checks again for a Kindle version of Humble Pi....dang it!
Why did I enjoy this video so much lol
823 is the route number for the new highway bypass around Portsmouth, Ohio, which ought to be opening any week now
parker answer
I love the negative days. But I wouldn't bother with day 0. For culture reasons.
Also, I ought to send you my unit converter at some point. It's not a traditional calculator, but I think it's cool.