For year codes, I just realized there's also a pattern to the 00-99 year codes: +6, +5, +6, +11. Look at years for code 0: 05, 11, 16, 22, 33, 39, 44, 50, 61... And so on until 95, at which point you can't add 5 without passing 99, so that's when the "1" year codes start, picking up where the pattern left off. It goes all the way to the final "6" year, '94.
This is great. I actually learned a slightly different way to do this. Sunday is NONE day - 0 Monday is ONE day - 1 Tuesday is TWOS day -2 Wednesday starts with W which has THREE points - 3 Thursday is FOURS day - 4 Friday is FIVES day - 5 Saturday is SIX turday - 6 January is WINTER time (6 letters in winter) - 6 February is the SECOND month - 2 March TWO the beat - 2 April FOOLS (5 letters in fools) - 5 May-O (as in mayonnaise) - 0 June BUG (3 letters in bug) - 3 July - FIVERworks - 5 August BBQ use A-1 steak sauce - 1 September - ( I personally use the square root of my birthday the 16th) - 4 October, Halloween, Devil, 666 - 6 November we eat TWOrkey for Thanksgiving - 2 December we have XMAS (4 letters) - 4 For the years in the 2000s I calculate like this 2001 = 1 2002 = 2 2003 = 3 2004 = 5 (one more is added because of leap year, so every 4 years goes up by 5, and the rest by 1) 2005 = 6 2006 = 7 or 0 (This goes back to modular where you want the numbers to be between 0 to 6, so I subtract by 7) 2007 = 1 2008 = 3 (leap year) 2009 = 4 2010 = 5 2011 = 6 2012 = 8 minus 7 = 1 (numbers divisible by 12 are great to calculate higher years as you divide the last two digits by 12 to get the value) 2024 = 2 ( 24/12 = 2) 2036 = 3 2048 = 4 2060 = 5 2072 = 6 2084 = 7 or 0 2096 = 8 or 1 (So if the year I'm calculating is 2091, I start at 2084 which is 7 or 0, 2088 is 5 more and 2091 is 3 more, (0+5+3 = 8 - 7 = 1) so 2091 is 1. So, for February 20, 2020: February = 2 20th = 20 - 7 = 13 - 7 = 6 ( or 20 - 14 = 6) For the year I start at 2012 which is 1. every 4 years I add 5, so 2016 is 1 + 5 = 6, and 2020 is 6 + 5 = 11. Subtract 7 to get 4. Also because February 29 of that year hasn't happened, I subtract 1 to get 3. (This can be the hardest thing to remember) Finally add 2 (for the month), 6 (for the day), and 3 (for the year) to get 11. Subtract 7 to get 4 or FOURSday AKA Thursday. For the 1900's I add one more. So February 20, 1920, was a Friday
@@hiteshpatel9567 Yes. For 2000 add 0 For 1900 add 1 For 1800 add 3 For 1700 add 5 For 1600 add 0 and the future as well 2100 add 5 2200 add 3 2300 add 1 2400 add 0 I'm sure you can see the pattern.
Nelson, you are awesome. I doubt you need to hear this, but I am absolutely fascinated and impressed with what you do. I just finished watching Memory Games and it's moving to see how much purpose you have behind what you're doing. I'm inspired and I'm not alone. Thank you for doing what you do!
I came from his Morse Code video, then ASL Language video, and now I'm here and my mind is exploding! just kidding! hehe.. have a happy time memorizing and calculating guys!
Wow, you actually memorized the years :D Hope you get some more recognition, your videos are awesome! I can assure you guys, the calculation is not that complicated if you practice it a bit (if you don't want to memorize it). It becomes rather intuitive. For anyone interested in learning the calculation, I have a video on my channel, and you can also find scripts there for practicing the year codes. I use a slightly different number system though, but you can change that in the script to adapt it to your method. But yeah, you won't reach the incredible speed that people who memorize the year codes do.
Thanks for the video Nelson. This may have shown up elsewhere in the comments, but I see that when calculating the "Century Code", the century with the value of 0 also corresponds to a leap year (ie divisible by 400).
I cut out learning all the years by using your equation for the years and the using modular division method on all the numbers to make them easier to manage. Im sure it would be even faster to memorise the years but I didn't feel like sitting down to memorise all that. I memorised everything I needed to within the space of this one video, which is awesome.
You can calculate any day of any year. Just remember 100 years has 5 odd days , 200 years has 3 odd days and 300 has 1 odd days. ..... . Give codes to days. Sunday - 0 , Monday-1, Tuesday-2 , Wednesday-3 , Thursday-4 , friday- 5 , Saturday- 6 Ex. 20 august 1946 Split 1945 into three parts. 1600 - 0 odd days , 300- 1 odd days , Divide 45 /4 =11 leap years. 34 normal years. Normal year always has 1 odd days and leap year always has 2 odd days . Therefore 34 ×1 = 34 odd days , and 11 ×2 =22 odd days. Total odd days are 22+34=56 odd days .Divide 56 by 7 . 56/7 we get 0 remainder. So we got 1 odd day from 300 years. Now calculate odd days from January 1946 to 20 august 1946. January is of 31 days so when you divide by 7 you get 3 remainder which is the odd days. Similarly in Feb you got 28 days in normal year and 29 in leap year. Since 1946is not a leap year i.e, 0 odd days . March - 3 odd days, April-2 odd days , May -3, June - 2 , July -3, and 20 days of August. Now cancel 7 by adding odd days of January , april and June . 3+2+2=7. So remaining odd days are 3 from march + 3 from may + 3 from July+20 days of August =29. Now divide 29 by 7 and you'll get 1 remainder which is an odd day. Now 1 +1 of 300 years=2 . . 2 is Tuesday.
Is there any way to get recognized for a new algorithm? I don't know much about patents or anything, but i have a new algorithm i wrote which easily and quickly converts between A.D to B.C any given date. I have both algorithms, Julian and Gregorian. For example, i was born on Friday, March 19, 1982. However, March 19, 1982B.C. was a Tuesday on the Gregorian B.C calendar, which wasn't in use yet, and so on the old Julian calendar March 19, 1982B.C was a Saturday. To go deeper, if we still want to know what A.D. March 19, 1982 was on the old Julian Calendar, it was a Thursday. So, we can actually calculate, (which I've never seen anyone else besides myself do) 4 different answers for a given date. MARCH 19, 1982: 1) Julian B.C (SATURDAY) 2) Julian A.D (THURSDAY) 3) Gregorian B.C (TUESDAY) 4) Gregorian A.D (FRIDAY)
I'm very happy to have found your channel, Nelson. This technique is indeed very interesting. However, from what I've analyzed, it doesn't always work. I tested some dates here, and using the numbers you provided, I got some conflicting results. I'd like you to watch the video “The Doomsday Algorithm - Numberphile” here on YT. Note that the professor manages codes that are different from yours when it comes to the year.
I use a slightly different set of offsets for the months. I did the calculations for the years (number of 4s + %7), which worked, but was not very efficient. Then I used a bastardised version of Dominic O'Brien's technique of putting people (or in my case objects) in different areas of my house that represent year offsets - eg, in my number system 47=rat in my kitchen (number 2). Months - Jan (1), Feb (4) etc ... for 1900s Years - 00 = 0, 01 = 1 etc Resulting days - Sat = 0, Sun = 1 etc So, July (0) 19th (5) 1947 (2) = 0 (Saturday) This, for 1900s (when I first looked at this - I'm THAT old!) had the advantage of year 00 being offset 0, and January (1st month) being 1 etc
What to do if the final result is not divisible by 7 like 5 or 6? Edit: It looks like if the final result is less than 7 then that number is the final day code But I'm not sure if it will always work Edit: After a quick google search of 6 modulus 7 the result is 6 itself maybe it's how modulus work
You got it. It would be that number. Any number mod a number greater than itself, is that number. i.e. 6 mod 1000 = 6, 23 mod 24 = 23, and thus, 5 mod 7 = 5.
Hey Daniel, check out the video at 9:36. I show it briefly. Here it is if you want to do it: (2-digit-year + [2-digit-year/4] + 1) % 7 ( [ ] means integer division and % means modular division)
My calculations take a little longer but I use two different methods for each date and check the answers against each other. There is what I call the "classic" method, which is the method shown in this video, and the "odd+11" version of the Doomsday algorithm (look it up under the "Doomsday rule" section of Wikipedia). If I get the same day of the week using these two different methods then I'm almost 100% sure that my answer is accurate. I've never been wrong in that case after checking both answers against the perpetual calendar. If I use just one method, there is a chance I'll make a mistake and not catch it.
Help! I applied the formula, but something went wrong. I was born on 12 of February of 1995, which was a Sunday, but I calculate a Monday. So 12 plus February (1) equals 13, plus XXth century (1) equals 14, which is 7 x 2, id est, zero. So we are left with with 95. So I apply the formula -> (95 + [95 / 4] + 1) % 7. 23 times four equals 92, so there are 3 left -> (95 + 3 + 1) % 7 -> 99 % 7... equals 1. 1 is Monday. But you yourself said 95 = 0 and, I checked it, it should be zero, id est, Sunday. What did I do wrong? 😭
I think a slight adjustment to the formula is needed, which is that the first year is also moded. so it should be something like [(year % 7) + rounddown(year,4) + 1] % 7. So as you said since everything else already nets out to 0 and we just need to figure out 95, it would be 95%7 (which is 4) + 95/4 (which is 23.x) + 1 -> 4+23+1 -> 28 % 7 -> 0. 3 months late but hope that helps!
When you are dividing the 95 by 4, use integer division. You don’t need to know the remainder for this specific part of the equation. It should be (95+[95/4]+1)%7 (95+[23]+1)%7 (119)%7 119/7= 17, remainder 0. That means the formula for the year gives you “0” to plug in to the rest of the day calculation formula.
I am confused, in Domonic's book Quantum Memory Power he has different numbers for the month codes than you do. How can you both have different numbers for the month codes and both end up with the correct total or day of the week?
Hi Nelson, the calendar calculation for 31 Jan 1651 is incorrect. Not Tuesday but Friday. Understand some difference is needed in the codes. I have developed very easy codes to calculate weekday names across 1000 million years anting from 1-1-0001 to any year unlimitedly. Thank you.
Namaste sir can you make video on memorising multiplication table because while calculating students get stuck like 51/119 if we memorised times table we can get answer quickly 3/7 is answer 17×3 and 17×7.... please make a video on memorising multiplication tables🙏
I don't just do 100 years or 2. I can do any date in history, in both B.C and A.D and also the old Julian Calendar and our current Gregorian Calendar until infinitely into the future.
YEAR CODE Formula is in the description 😊 Lemme explain so, LOOK on last two digits (LTD) [ (Ltd + Ltd/4 ) + 1 ] = year code but if it is obove 7 then divide by 7 and the remainder is year code Eg: 2004 Last two digits (Ltd) = 4 So, put in formula [ ( 4 + 4/4 ) + 1 ] = 6
@@peaceful160how about 2097? ltd is 97, so.... 25 + (97/4) + 1 25 + (24,25) + 1 I need to know the integer division. I need to know what to do if the ltd/4 has reminder like i said above. Thanks. I hope u can answer that
Help me out here 20 feb 2023. 1 for feb, 1 for 2023, 20 for the date. Equals 22. 22 goes into 7 3 times remainder is 1 … 1 is supposed to be Monday but when you look at calendar it’s actually Wednesday 🤔
Nelson, People claim to be able to do this 140 times without a mistake in 60 seconds between the years 1600-2100. This means they are coming up with the correct answer 2.3 times per SECOND. Do you believe this is possible?
@@NymphaMemphis I'd love to talk to your son, I'm curious which method he uses. I can do one to two dates every 2 seconds. I probably average about 2 dates every 3 seconds, like 1.5 seconds each.
@@thecalendargod6065 he would like that. He used to randomly tell us the day something happened. Like if I spoke about a random date in 2000 (before he was born) he would tell me the day. I only recently stated taking him seriously and one day I just started firing out dates and he would give the days. He would think about it for like 3-5 seconds and would give the correct answer. I asked him how and he said “I don’t know, my mind just tells me “ 😂😂
@@NymphaMemphis that's so 😎cool! I'm impressed. I'd love to chat with him about calendars. I'm sure we can learn from one another. And, if he's interested, i can share with him some cool calendar tricks i do that you don't hear of very often. I can do questions such as: What was the 4th Thursday of June in 1867? I would say, "the 27th" for example.
@Eduardo Lenz Cesar Xenofonte Yusnier Viera did it, you can even watch it on TH-cam, he's from Cuba. The way he does it is on a computer program which shows listed random dates, then he presses a button on his keyboard corresponding to each of the 7 days of the week. He actually starts calculting the next date down the list while keying in the previous answer, it is very impressive to say the least, and it's 100 percent real, as he is in the Guiness Book for this.
No you don't have to, you can calculate them. It's YC = (year + round_down(year / 4) + 1) mod 7. Examples: year = 73 -> (73 + round_down(73 / 4) + 1) mod 7 = (73 + round_down(18.25) + 1) mod 7 = (73 + 18 + 1) mod 7 = 92 mod 7 = 92 - 91 = 1 year = 23 -> (23 + 5 + 1) mod 7 = 29 - 28 = 1 year = 56 -> (56 + 14 + 1) mod 7 = 71 - 70 = 1 year = 98 -> (98 + 24 + 1) mod 7 = 123 - 119 = 4 If you wonder where the numbers 91,28, 70 and 119 come from, they are multiples of 7 closest to our numbers. It's the easiest way to calculate modulo operation. If you are interested in practicing the calculations, I have a video on that and you find scripts for practicing the calculations there, however, I use a slightly different number system. th-cam.com/video/0BiCICewG5c/w-d-xo.html If you want to do it really quickly, like Nelson Dellis, then you have to memorize the years. I need about 5-7 seconds for a date, but it also takes some time practicing the formulas to get your speed down. With little practice, you can still achieve 10-15s for a date.
The formula works, because each year shifts the weekdays by 1 -> meaning that, if you add a year to your current date, and you now have a monday, the next year you will have a tuesday. However, each leap year shifts the weekdays by 2. So, what this formula does is we first take the year (we add the number 1 for each year) and then we divide it by 4 to find out how many leap years have occurred between our year and the beginning of the century. By adding this to the year, we add another 1 for each leap year. So in the end, for each year we added +1 and for each leap year we added +2.
I learned the doomsday algorithm The doomsdays are 1/3 or 1/4 on leap years 2/28 or 2/29 on a lepa year 3/14 4/4 5/9 6/6 7/11 8/8 9/5 10/10 11/7 12/12 The way you do the days is the same Century doomsday 1700 sunday 1800 Friday 1900 Wednesday 2000 Tuesday This repeats To find the doomsday you look at the century so I'll do today 2023 2023 is in the 2000s so it is a Tuesday in that year So now you have 2 Add the years, so 23 Then add the leap years, so 5 leap years 23+5=28 28+2=30 Now you need to just divide by 7 and keep the remainder so 30/7 has a remainder of 2 So the doomsday of 2023 is tuesday For leap years, you add 2 So the doomsday next year is Thursday Go chdck out numberphile The Gregorian calendar repeats every 28 years, so you can simplify So 1982 as an example 28, 56 Subtract 56 for 82 Thats 26 So now you add 26 The doomsday for 1900 is Wednesday 26+3+6 leap years 35 35/7 =5 with 0 reminder So the doomsday for this year is sunday
9:12 and 12:01 are where you’ll find that answer. The centuries repeat, it’s either 5,3,1,0. For the 2 digit year, that’s the one that takes the most effort to learn, or you can learn the formula and do it in your head.
@@zeinabalfatih1437 okay so on the first sheet I told you to look at you can see 2000s are 0. The year 01 is 2 (you can see that on the other sheet). So 2001 is 0+2.
@@zeinabalfatih1437 to be clear, ALL 2000s century codes are a 0. So 2000, 2001, 2023, 2055, whatever, the century codes are all 0. You just need to look up the year code for 00, 01, 23, 55, etc, to get the full year code
With my way, I actually memorize every single year code, as you mentioned is the best way. We can combine it with a century code and then it doesn't just cover a few years, it covers any year ever past or future infinitely into the future for both Julian and Gregorian Calendars. I can solve for any date imaginable in under 2 seconds flat.
Nice video! Exactly the same system I am using (exept that my month code is +1 and my year code -1 relative to your system). Just out of curiosity, how fast can you do it? My best score is 10 in a minute using memoriad simulator, which is not bad, but I know a guy who did 40 in a minute in competition (here is a video of him showing off a bit doing 29 in a minute while singing: th-cam.com/video/P5maKEmqInk/w-d-xo.html). World record is 140 in a minute! The guy probably memorized the codes for all the years from 1600 to 1999 and all the days of the year (766 codes in total), something anyone with a 3 digit system can probably do with a bit of practice...but still, 140 is just crazy!
Hey, thank you! My best was 20 when I was training more. That was a few years ago. My good friend Yusnier is that record holder and the method I teach here is directly from him! He has just done this for so long that he just "knows" the answers. It's pretty incredible to see him in action.
What day of the week were you born? Can you calculate it?
I was a SATURDAY oh yeahhhhh
On Jan 9 2004
Really
I didn't know the day.
Thanks anyway love your method.
Just finished Morse code! Epic vid
This channel is underrated :< His videos must have millions of views!! It's great so practical! You inspire peoples
For year codes, I just realized there's also a pattern to the 00-99 year codes: +6, +5, +6, +11. Look at years for code 0: 05, 11, 16, 22, 33, 39, 44, 50, 61... And so on until 95, at which point you can't add 5 without passing 99, so that's when the "1" year codes start, picking up where the pattern left off. It goes all the way to the final "6" year, '94.
This is great. I actually learned a slightly different way to do this.
Sunday is NONE day - 0
Monday is ONE day - 1
Tuesday is TWOS day -2
Wednesday starts with W which has THREE points - 3
Thursday is FOURS day - 4
Friday is FIVES day - 5
Saturday is SIX turday - 6
January is WINTER time (6 letters in winter) - 6
February is the SECOND month - 2
March TWO the beat - 2
April FOOLS (5 letters in fools) - 5
May-O (as in mayonnaise) - 0
June BUG (3 letters in bug) - 3
July - FIVERworks - 5
August BBQ use A-1 steak sauce - 1
September - ( I personally use the square root of my birthday the 16th) - 4
October, Halloween, Devil, 666 - 6
November we eat TWOrkey for Thanksgiving - 2
December we have XMAS (4 letters) - 4
For the years in the 2000s I calculate like this
2001 = 1
2002 = 2
2003 = 3
2004 = 5 (one more is added because of leap year, so every 4 years goes up by 5, and the rest by 1)
2005 = 6
2006 = 7 or 0 (This goes back to modular where you want the numbers to be between 0 to 6, so I subtract by 7)
2007 = 1
2008 = 3 (leap year)
2009 = 4
2010 = 5
2011 = 6
2012 = 8 minus 7 = 1 (numbers divisible by 12 are great to calculate higher years as you divide the last two digits by 12 to get the value)
2024 = 2 ( 24/12 = 2)
2036 = 3
2048 = 4
2060 = 5
2072 = 6
2084 = 7 or 0
2096 = 8 or 1
(So if the year I'm calculating is 2091, I start at 2084 which is 7 or 0, 2088 is 5 more and 2091 is 3 more, (0+5+3 = 8 - 7 = 1) so 2091 is 1.
So, for February 20, 2020:
February = 2
20th = 20 - 7 = 13 - 7 = 6 ( or 20 - 14 = 6)
For the year I start at 2012 which is 1. every 4 years I add 5, so 2016 is 1 + 5 = 6, and 2020 is 6 + 5 = 11. Subtract 7 to get 4. Also because February 29 of that year hasn't happened, I subtract 1 to get 3. (This can be the hardest thing to remember)
Finally add 2 (for the month), 6 (for the day), and 3 (for the year) to get 11. Subtract 7 to get 4 or FOURSday AKA Thursday.
For the 1900's I add one more.
So February 20, 1920, was a Friday
thanks
You are fabulous thanks
Hey Edgar.. thanks for those mnemonic tips on the month codes. I am using them as part of my video description :)
Bro you can learn 500 year calendar
@@hiteshpatel9567 Yes.
For 2000 add 0
For 1900 add 1
For 1800 add 3
For 1700 add 5
For 1600 add 0
and the future as well
2100 add 5
2200 add 3
2300 add 1
2400 add 0
I'm sure you can see the pattern.
Thank you for telling us how to determine if it is a leap year!!
I have tried to learn this before and got stumped on that 👍🏼
Sir. It's really hard for me to memorize but because of your videos. Little by little i could remember things longer than I could
Nelson, you are awesome. I doubt you need to hear this, but I am absolutely fascinated and impressed with what you do. I just finished watching Memory Games and it's moving to see how much purpose you have behind what you're doing. I'm inspired and I'm not alone. Thank you for doing what you do!
Wow!! Thank you so much! You deserve so many more subs😄
I was just looking for some new stuff to remember, really cool and helpful video, appreciate it, thx! :)
I came from his Morse Code video, then ASL Language video, and now I'm here and my mind is exploding! just kidding! hehe..
have a happy time memorizing and calculating guys!
Wow, you actually memorized the years :D Hope you get some more recognition, your videos are awesome!
I can assure you guys, the calculation is not that complicated if you practice it a bit (if you don't want to memorize it). It becomes rather intuitive. For anyone interested in learning the calculation, I have a video on my channel, and you can also find scripts there for practicing the year codes. I use a slightly different number system though, but you can change that in the script to adapt it to your method. But yeah, you won't reach the incredible speed that people who memorize the year codes do.
Thanks for the video Nelson. This may have shown up elsewhere in the comments, but I see that when calculating the "Century Code", the century with the value of 0 also corresponds to a leap year (ie divisible by 400).
Thanks. I'm done memorizing the codes using my amazing PAO system.
he deserves much more likes .. excellent for giving the world so much new innovative skills.
I cut out learning all the years by using your equation for the years and the using modular division method on all the numbers to make them easier to manage. Im sure it would be even faster to memorise the years but I didn't feel like sitting down to memorise all that. I memorised everything I needed to within the space of this one video, which is awesome.
This is so funny, I was just researching this earlier today and you made a video.
You can calculate any day of any year.
Just remember 100 years has 5 odd days , 200 years has 3 odd days and 300 has 1 odd days. .....
.
Give codes to days.
Sunday - 0 ,
Monday-1, Tuesday-2 , Wednesday-3 , Thursday-4 , friday- 5 , Saturday- 6
Ex. 20 august 1946
Split 1945 into three parts.
1600 - 0 odd days , 300- 1 odd days , Divide 45 /4 =11 leap years. 34 normal years.
Normal year always has 1 odd days and leap year always has 2 odd days . Therefore 34 ×1 = 34 odd days , and 11 ×2 =22 odd days. Total odd days are 22+34=56 odd days .Divide 56 by 7 .
56/7 we get 0 remainder. So we got 1 odd day from 300 years.
Now calculate odd days from January 1946 to 20 august 1946.
January is of 31 days so when you divide by 7 you get 3 remainder which is the odd days. Similarly in Feb you got 28 days in normal year and 29 in leap year. Since 1946is not a leap year i.e, 0 odd days .
March - 3 odd days, April-2 odd days , May -3, June - 2 , July -3, and 20 days of August.
Now cancel 7 by adding odd days of January , april and June . 3+2+2=7.
So remaining odd days are 3 from march + 3 from may + 3 from July+20 days of August =29.
Now divide 29 by 7 and you'll get 1 remainder which is an odd day. Now 1 +1 of 300 years=2 . .
2 is Tuesday.
Could you please post a vid of how you calculated both the month and the year codes?
Is there any way to get recognized for a new algorithm? I don't know much about patents or anything, but i have a new algorithm i wrote which easily and quickly converts between A.D to B.C any given date. I have both algorithms, Julian and Gregorian. For example, i was born on Friday, March 19, 1982. However, March 19, 1982B.C. was a Tuesday on the Gregorian B.C calendar, which wasn't in use yet, and so on the old Julian calendar March 19, 1982B.C was a Saturday. To go deeper, if we still want to know what A.D. March 19, 1982 was on the old Julian Calendar, it was a Thursday.
So, we can actually calculate, (which I've never seen anyone else besides myself do) 4 different answers for a given date.
MARCH 19, 1982:
1) Julian B.C (SATURDAY)
2) Julian A.D (THURSDAY)
3) Gregorian B.C (TUESDAY)
4) Gregorian A.D (FRIDAY)
I'm very happy to have found your channel, Nelson. This technique is indeed very interesting. However, from what I've analyzed, it doesn't always work. I tested some dates here, and using the numbers you provided, I got some conflicting results. I'd like you to watch the video “The Doomsday Algorithm - Numberphile” here on YT. Note that the professor manages codes that are different from yours when it comes to the year.
It's enough, I'm subscribed!
I use a slightly different set of offsets for the months. I did the calculations for the years (number of 4s + %7), which worked, but was not very efficient. Then I used a bastardised version of Dominic O'Brien's technique of putting people (or in my case objects) in different areas of my house that represent year offsets - eg, in my number system 47=rat in my kitchen (number 2).
Months - Jan (1), Feb (4) etc ... for 1900s
Years - 00 = 0, 01 = 1 etc
Resulting days - Sat = 0, Sun = 1 etc
So, July (0) 19th (5) 1947 (2) = 0 (Saturday)
This, for 1900s (when I first looked at this - I'm THAT old!) had the advantage of year 00 being offset 0, and January (1st month) being 1 etc
At 12:05, there is an error, for the 0: code, the number between 22 and 39 should be 33 not 23.
could you make a video on the calculation for the year codes?
what if there's no remainder? Then its automatically sunday?
i can do this quite good because i know a LOT of people's birthdays so it is easy to subtract or add from that day
What to do if the final result is not divisible by 7 like 5 or 6?
Edit: It looks like if the final result is less than 7 then that number is the final day code
But I'm not sure if it will always work
Edit: After a quick google search of 6 modulus 7 the result is 6 itself maybe it's how modulus work
You got it. It would be that number. Any number mod a number greater than itself, is that number. i.e. 6 mod 1000 = 6, 23 mod 24 = 23, and thus, 5 mod 7 = 5.
@@NelsonDellisthanks for clarifying
You deserve at least 1 million subs
I thought you were going to teach how to calculate the year code on the fly. I can't find the calculation on the link you provided.
Hey Daniel, check out the video at 9:36. I show it briefly. Here it is if you want to do it:
(2-digit-year + [2-digit-year/4] + 1) % 7
( [ ] means integer division and % means modular division)
@@NelsonDellis thanks, I must have missed it
My calculations take a little longer but I use two different methods for each date and check the answers against each other. There is what I call the "classic" method, which is the method shown in this video, and the "odd+11" version of the Doomsday algorithm (look it up under the "Doomsday rule" section of Wikipedia). If I get the same day of the week using these two different methods then I'm almost 100% sure that my answer is accurate. I've never been wrong in that case after checking both answers against the perpetual calendar. If I use just one method, there is a chance I'll make a mistake and not catch it.
Help! I applied the formula, but something went wrong. I was born on 12 of February of 1995, which was a Sunday, but I calculate a Monday. So 12 plus February (1) equals 13, plus XXth century (1) equals 14, which is 7 x 2, id est, zero. So we are left with with 95. So I apply the formula -> (95 + [95 / 4] + 1) % 7. 23 times four equals 92, so there are 3 left -> (95 + 3 + 1) % 7 -> 99 % 7... equals 1. 1 is Monday. But you yourself said 95 = 0 and, I checked it, it should be zero, id est, Sunday. What did I do wrong? 😭
I think a slight adjustment to the formula is needed, which is that the first year is also moded. so it should be something like [(year % 7) + rounddown(year,4) + 1] % 7. So as you said since everything else already nets out to 0 and we just need to figure out 95, it would be 95%7 (which is 4) + 95/4 (which is 23.x) + 1 -> 4+23+1 -> 28 % 7 -> 0. 3 months late but hope that helps!
The formula is correct, you said "23 times four equals 92, so there are 3 left" but it's actually 2 left there
When you are dividing the 95 by 4, use integer division. You don’t need to know the remainder for this specific part of the equation.
It should be
(95+[95/4]+1)%7
(95+[23]+1)%7
(119)%7
119/7= 17, remainder 0.
That means the formula for the year gives you “0” to plug in to the rest of the day calculation formula.
I am confused, in Domonic's book Quantum Memory Power he has different numbers for the month codes than you do. How can you both have different numbers for the month codes and both end up with the correct total or day of the week?
As long as the numbers equal the offsets for the days, it all works. I use the DOB method (or a version of it) and it still works
Hi Nelson, the calendar calculation for 31 Jan 1651 is incorrect. Not Tuesday but Friday. Understand some difference is needed in the codes. I have developed very easy codes to calculate weekday names across 1000 million years anting from 1-1-0001 to any year unlimitedly. Thank you.
It is correct in the Gregorian calandar
@@totleariss Prior to 13th September 1752 we used the Julian calendar so Friday is correct.
Sir, how you can do that ? Teach-me, hug from Portugal 🇵🇹
Namaste sir can you make video on memorising multiplication table because while calculating students get stuck like 51/119 if we memorised times table we can get answer quickly 3/7 is answer 17×3 and 17×7.... please make a video on memorising multiplication tables🙏
you could also remember april as the 4th month in the year. but, yours works too i guess
what if the total at the end is less that 7 for ex
1 sept 2045
1+3+0+1=5.....Nothing to divide by 7
Then it's just 5 - Friday, isn't it?
There IS something to divide by 7, the 5
5/7 is Zero, and Remainder 5
What matters is the REMAINDER and not the actual answer to the division.
thanyouuuuu ....it was very helpful
I think the doomsday rule is easier than adding for each month.
I don't just do 100 years or 2. I can do any date in history, in both B.C and A.D and also the old Julian Calendar and our current Gregorian Calendar until infinitely into the future.
Love u man
Can u do a video on remembering medical terms
Yes please
I think mullenmemory.com has a lot on that
Why is 03 Jack Black? From the PAO video, 03 initials would be O and C, not J and B...
How come some numbers repeat themselves in the advanced year codes like 23 is in the 0’s and 1’s? Someone please explain
How we will calculate for 31,MARCH, 2020?? my answer is coming out to be incorrect..
Has he shown to add 31?? Just asking
Oh thanks I might have missed it.. 😄
pre-order done!!
could you explain how we would calculate the year using the formula please, thank you!
YEAR CODE
Formula is in the description 😊
Lemme explain
so, LOOK on last two digits (LTD)
[ (Ltd + Ltd/4 ) + 1 ] = year code but if it is obove 7 then divide by 7 and the remainder is year code
Eg: 2004
Last two digits (Ltd) = 4
So,
put in formula
[ ( 4 + 4/4 ) + 1 ] = 6
@@peaceful160how about 2097?
ltd is 97, so....
25 + (97/4) + 1
25 + (24,25) + 1
I need to know the integer division.
I need to know what to do if the ltd/4 has reminder like i said above. Thanks. I hope u can answer that
@@bimorizki sorry bro I forget it its 6 month ago lol 😂
There is no need to remember the month code. A Vietnamese guy developed a formular for the month code.
I like all those meme that you included in your video lol
Really genius.
I'll try it tomorrow if i remember 😂
You only need the year code from 00 to 27.
Hey, do you recommend any podcasts?
How are you do it is based off of events that I can remember
Thanks Nelson sir
Help me out here 20 feb 2023. 1 for feb, 1 for 2023, 20 for the date. Equals 22. 22 goes into 7 3 times remainder is 1 … 1 is supposed to be Monday but when you look at calendar it’s actually Wednesday 🤔
February 20th, 2023 is actually a Monday silly 😂
Feb (Month) = 1
2023 (Year) = 1
20 (Day)= 20
1 + 1 + 20 = 22
22 ÷ 7 = 3 r1
1 = Monday
February 20, 2023 is a Monday.
This is different than the DOOMSDAY principle... More straight forward, but a bit more memory.
Nelson, People claim to be able to do this 140 times without a mistake in 60 seconds between the years 1600-2100. This means they are coming up with the correct answer 2.3 times per SECOND. Do you believe this is possible?
My son can
@@NymphaMemphis I'd love to talk to your son, I'm curious which method he uses. I can do one to two dates every 2 seconds. I probably average about 2 dates every 3 seconds, like 1.5 seconds each.
@@thecalendargod6065 he would like that. He used to randomly tell us the day something happened. Like if I spoke about a random date in 2000 (before he was born) he would tell me the day. I only recently stated taking him seriously and one day I just started firing out dates and he would give the days. He would think about it for like 3-5 seconds and would give the correct answer. I asked him how and he said “I don’t know, my mind just tells me “ 😂😂
@@NymphaMemphis that's so 😎cool! I'm impressed. I'd love to chat with him about calendars. I'm sure we can learn from one another. And, if he's interested, i can share with him some cool calendar tricks i do that you don't hear of very often. I can do questions such as: What was the 4th Thursday of June in 1867? I would say, "the 27th" for example.
@Eduardo Lenz Cesar Xenofonte Yusnier Viera did it, you can even watch it on TH-cam, he's from Cuba. The way he does it is on a computer program which shows listed random dates, then he presses a button on his keyboard corresponding to each of the 7 days of the week. He actually starts calculting the next date down the list while keying in the previous answer, it is very impressive to say the least, and it's 100 percent real, as he is in the Guiness Book for this.
How do u know the year codes do u just have to memorise them?
No you don't have to, you can calculate them. It's YC = (year + round_down(year / 4) + 1) mod 7. Examples:
year = 73 -> (73 + round_down(73 / 4) + 1) mod 7 = (73 + round_down(18.25) + 1) mod 7 = (73 + 18 + 1) mod 7 = 92 mod 7 = 92 - 91 = 1
year = 23 -> (23 + 5 + 1) mod 7 = 29 - 28 = 1
year = 56 -> (56 + 14 + 1) mod 7 = 71 - 70 = 1
year = 98 -> (98 + 24 + 1) mod 7 = 123 - 119 = 4
If you wonder where the numbers 91,28, 70 and 119 come from, they are multiples of 7 closest to our numbers. It's the easiest way to calculate modulo operation.
If you are interested in practicing the calculations, I have a video on that and you find scripts for practicing the calculations there, however, I use a slightly different number system. th-cam.com/video/0BiCICewG5c/w-d-xo.html
If you want to do it really quickly, like Nelson Dellis, then you have to memorize the years. I need about 5-7 seconds for a date, but it also takes some time practicing the formulas to get your speed down. With little practice, you can still achieve 10-15s for a date.
The formula works, because each year shifts the weekdays by 1 -> meaning that, if you add a year to your current date, and you now have a monday, the next year you will have a tuesday. However, each leap year shifts the weekdays by 2.
So, what this formula does is we first take the year (we add the number 1 for each year) and then we divide it by 4 to find out how many leap years have occurred between our year and the beginning of the century. By adding this to the year, we add another 1 for each leap year. So in the end, for each year we added +1 and for each leap year we added +2.
One Dislike may be from Calendar printing press.
I learned the doomsday algorithm
The doomsdays are
1/3 or 1/4 on leap years
2/28 or 2/29 on a lepa year
3/14
4/4
5/9
6/6
7/11
8/8
9/5
10/10
11/7
12/12
The way you do the days is the same
Century doomsday
1700 sunday
1800 Friday
1900 Wednesday
2000 Tuesday
This repeats
To find the doomsday you look at the century so I'll do today
2023
2023 is in the 2000s so it is a Tuesday in that year
So now you have 2
Add the years, so 23
Then add the leap years, so 5 leap years
23+5=28
28+2=30
Now you need to just divide by 7 and keep the remainder so 30/7 has a remainder of 2
So the doomsday of 2023 is tuesday
For leap years, you add 2
So the doomsday next year is Thursday
Go chdck out numberphile
The Gregorian calendar repeats every 28 years, so you can simplify
So 1982 as an example
28, 56
Subtract 56 for 82
Thats 26
So now you add 26
The doomsday for 1900 is Wednesday
26+3+6 leap years
35
35/7
=5 with 0 reminder
So the doomsday for this year is sunday
What about using the power of the subconscious?
Fun learning
I can do this to without this vid just on my self
Nelson can you tell me when l can find the year codes from 2000 to 2100
9:12 and 12:01 are where you’ll find that answer. The centuries repeat, it’s either 5,3,1,0. For the 2 digit year, that’s the one that takes the most effort to learn, or you can learn the formula and do it in your head.
@@NelsonDellis l understand the code of centuries
but l need the code of 2001, 2023 , 2011 , 2099 as example for the years between 2000 and 2100
@@zeinabalfatih1437 okay so on the first sheet I told you to look at you can see 2000s are 0. The year 01 is 2 (you can see that on the other sheet). So 2001 is 0+2.
@@zeinabalfatih1437 to be clear, ALL 2000s century codes are a 0. So 2000, 2001, 2023, 2055, whatever, the century codes are all 0. You just need to look up the year code for 00, 01, 23, 55, etc, to get the full year code
@@NelsonDellis ok Thanks Nelson
wow super!!!!
I know 500 year calendar.
23 is in the 0s and 1s row for the advanced method. Which one is it?
Also, there is no 33, is the 23 in the 0s row supposed to be 33?
Good catch. The 23 in row "0" should be a 33. The full list is correct here: www.nelsondellis.com/memorize-the-calendar (sorry about that!).
How to calculate these code plz teach us
Pls more year code plssss☺️☺️🙏🙏🙏🙏🙏
WoW, It's tricky 🙂🙂🙂
Best!!
Sorry it didn't work for me 100%
perfect
Well I calculate all the years alone with paper yes I did
Fun fact: this video expires in 2025 (first video to have an expiration date)
?
Super!))
With my way, I actually memorize every single year code, as you mentioned is the best way. We can combine it with a century code and then it doesn't just cover a few years, it covers any year ever past or future infinitely into the future for both Julian and Gregorian Calendars. I can solve for any date imaginable in under 2 seconds flat.
😴
For those that want to practice this random.org can generate random dates
WOW
Doomsday is easier for me.
Monday 1 Tuesday 2 Wednesday 3 Thursday 4 Friday 5 Saturday 6 Sunday 7
Calendar wow 2020 7 years old calculate
I prefer the doomsday method.
2021 pls
August September September September September December January February
Nice video! Exactly the same system I am using (exept that my month code is +1 and my year code -1 relative to your system). Just out of curiosity, how fast can you do it? My best score is 10 in a minute using memoriad simulator, which is not bad, but I know a guy who did 40 in a minute in competition (here is a video of him showing off a bit doing 29 in a minute while singing: th-cam.com/video/P5maKEmqInk/w-d-xo.html). World record is 140 in a minute! The guy probably memorized the codes for all the years from 1600 to 1999 and all the days of the year (766 codes in total), something anyone with a 3 digit system can probably do with a bit of practice...but still, 140 is just crazy!
Hey, thank you! My best was 20 when I was training more. That was a few years ago. My good friend Yusnier is that record holder and the method I teach here is directly from him! He has just done this for so long that he just "knows" the answers. It's pretty incredible to see him in action.
2:44 - 2:52
That sounded... corny...
Make it easy