Skycastlefish Posted September 16, 2010 Share Posted September 16, 2010 (edited) As promised, here is a tutorial on how to figure out the day of the week for just about any date, past or future. Would you like to know what day your birthday will fall on in 4065? I don't know why you would want to know that, but you could figure it out in just a few seconds. It isn't rocket science . All it takes is a little bit of memorization and some basic math skills. I learned how to do this from a book called Secrets of Mental Math by Arthur Benjamin and Michael Shermer. It goes down in my personal history as the only how-to book with the word "secret" in the title that doesn't suck. 1.) The first thing you want to do is assign a code number for each day of the week. Number = Day 1=Monday 2=Tuesday 3=Wednesday 4=Thursday 5=Friday6=Saturday7 or 0=Sunday. I find the above code numbers easy to remember being that Monday feels like the first day of the week to me. If you find it difficult to remember, you can use things like 2's day = Tuesday or 3 fingers on one hand make up a W for Wednesday, etc. Whatever you need to do to remember. 2.) Next you need to memorize a code for every month. These number appear to be a bit more random than the weekdays, but still rather easy to remember. Especially with the following mnemonics. These month codes are the same for every year with two exceptions. In a leap year (2000, 2004, 2008...) the month codes for January is 5, and the month code for February is 1. January = 6* (W-I-N-T-E-R has 6 letters)February = 2* (February is the 2nd month of the year)March = 2 (March 2 the beat of the drum)April = 5 (A-P-R-I-L and F-O-O-L-S have 5 letters)May = 0 (Hold the May-0)June = 3 (June B-U-G has 3 letters)July = 5 (Watching FIVER-works and FIVER crackers) I don't know what to say If you forget that one...August = 1 (August begins with an A, the 1st letter)September = 4 (September is the beginning of F-A-L-L)October = 6 (Halloween T-R-I-C-K-S and T-R-E-A-T-S)November = 2 (I'll have 2 servings of TUrkey, please)December = 4 (December is the L-A-S-T month, or X-M-A-S) * In a leap year, the code for January is 5 and the code for February is 1 (one less than they are in non leap years) Edited September 17, 2010 by Skycastlefish Link to comment Share on other sites More sharing options...
Skycastlefish Posted September 16, 2010 Author Share Posted September 16, 2010 (edited) Formatting issues, hold on... Looks like I'll need to do this in more than one post Edited September 16, 2010 by Skycastlefish Link to comment Share on other sites More sharing options...
Skycastlefish Posted September 16, 2010 Author Share Posted September 16, 2010 (edited) 3.) The last number codes we need to know are the year codes. Each year has a code number between 0 and 6 and that number stays the same for the entire year. For example, 2010 has a year code of 5. Therefore, all dates in 2010 have the year code of 5. The good news is that we don't have to memorize all the year codes. We can calculate the year code for any date between 2000 and 2099. There are several ways to do this. Lets focus only on the years in the 21st century. Once you know how to calculate the year code for the 2000's you can figure out the year codes in the 1900s, 1800s, 2100s etc. a.) One way to calculate the year code is to... Take the last two digits of any year between 2000 and 2099. For example, 2061 would become 61. We'll call the last two digits of any year between 2000 and 2099, X. To find the year code divide X by 4 (ignoring any remainders) and add that to X. The year code can be reduced by subtracting the largest multiple of 7. For example, the above year 2061 has an X value of 61. Divide 61 by 4 (ignoring the remainder of 1) which is 15. Add that to X, 61+15=76. Divide 76 with the largest multiple of 7 (70) and you are left with the number 6. That means that the year code for 2061 is 6. Here is a shorthand view. X/4=YX+Y=ZZ - (largest multiple of 7) = Year code. 61/4=15 (ignoring remainder)61+15=7676-70 = 6 (Year code) b.) Another way of doing this is to start with the year 2000 having a year code of 0. For each year gained, add one the year code. The catch is that on a leap year you must add 2 to the previous year code. Remember that year codes are 0 - 6. So adding 1 to 6 = 0. Adding 2 to six is 1 (it keeps looping around.) Here's a list... 2000=02001=12002=22003=32004=5 (notice I added 2 because 2004 is a leap year.)2005=6 (back to adding 1)2006=0 (adding 1 to 6 takes you back to 0)2007=12008=3 (leap year.)And so on... c.) Lastly, you can write down a chart with the above two methods and use it as a reference. I don't advise this method if you want to use this as a trick. Later I'll reply to this thread with all the year codes between 2000 and 2020. TIP: If you aren't comfortable with doing lots of math in your head I recommend that you memorize the year codes for 2-5 years on either side of the present year. Its 2010 right now, so memorize the year code for 2011 and 2012, as well as 2009 and 2008. This way you can tell people the further away they get from the present date, the more difficult it is for you to recall the week day. Most people will not look down on you for not knowing the weekday of a date 6 years out. If you are not learning this method as a trick and only as a practical way of finding out dates then you only have to figure out a year code once per year. When 2011 rolls around figure out that the year code is 6 and you're set for every date for the rest of that year. Edited September 17, 2010 by Skycastlefish Link to comment Share on other sites More sharing options...
Skycastlefish Posted September 17, 2010 Author Share Posted September 17, 2010 (edited) 4. Now comes the fun part, figuring out the weekday of any date in the 21st century! As previously stated, once you figure out how to do this with all dates between 2000 and 2099, then you can find them for other centuries. Now, to calculate the day of the week, you simply add the month code plus the date plus the year code. Here's the formula... Month Code + Date + Year code = Day of the week! Lets figure out the day of the week for a few dates in 2006, which happens to have a year code of 0 December 3, 2006 4 (month code) + 3 (date) + 0 (year code)= 7 (day code)Hence, this date will be on day 7, which is a Sunday. If the sum is greater than 7, simply subtract the largest multiple of 7 and whats left over is your weekday, like this... September 12, 20064+12+0=1616 - 14 (largest multiple of 7) = 2Therefore, September 12, 2006 is a Tuesday Lets do one in 2010...December 12th, 2010 translates to...4+12+5=2121 - 21 (largest multiple of 7) = 0 (never forget that Sunday is both 0 and 7) 5.) Finally, to figure out the weekday for days in the 1900s, simply add one to the year code of the 2000's equivalent. For example, if the year code in 2010 is 5, then the year code for 1910 is 6. You just add one to the year code. For dates in the 1800s add 3 to the year code. For dates in the 2100s, we add 5 to the year code. For example, since 2009 has a year code of 4, then 2109 has a year code of 4+5=9, which after subtracting 7 (any number above 7 has to be reduced by the largest multiple of 7) is the same as the year code 2. The Gregorian calender repeats every 400 years so you can convert any future date into a date near 2000. For example, March 19, 2761 will have the same day of the week as March 19, 1961. Remember that the Gregorian calender was not adopted by England (and the American colonies) until 1752. I hope you guys enjoy learning this skill. It looks very complicated, but once you memorize the month codes it is pretty smooth skating. It you make a habit of figuring out the day for every date you hear in your day to day life, even if its only quietly in your head, you will stay polished and quick. Next time your at a party, find a clever way to segue into bringing up this "talent." Then have your friends pull out their phone calender and ask them to spout off dates. Usually they'll either be giggling and amazed or quietly starring at their calender seriously trying to figure out a way to stump you. If you then mention that you build rockets, they will really think you're a genius, which may or may not be true. The point is, its entertaining to entertain people. Have fun! Here are a few examples for you to practice on... 1.) February 19, 20072.) March 14, 20123.) September 1, 19834.) July 22, 22225.) June 30, 2468 If the first person to answer these correctly (and show their work) lives in the USA, I'll ship you 5 free 1 in ID card tubes like this one... http://www.amateurpy...__1entry54810 PS Please let me know if you find any mistakes above. Its easy to make typos when dealing with numbers, not to mention the difficulty in getting this thread in format. Edited September 17, 2010 by Skycastlefish Link to comment Share on other sites More sharing options...
Skycastlefish Posted September 17, 2010 Author Share Posted September 17, 2010 Year Codes for 2000-2020 2000=0 (leap year)2001=12002=22003=32004=5 (leap year)2005=62006=02007=12008=3 (leap year)2009=42010=52011=62012=1 (leap year)2013=22014=32015=42016=6 (leap year)2017=02018=12019=22020=4 (leap year) Link to comment Share on other sites More sharing options...
NightHawkInLight Posted September 17, 2010 Share Posted September 17, 2010 1.) February 19, 2007 - Monday2.) March 14, 2012 - Wednesday3.) September 1, 1983 - Wednesday4.) July 22, 2222 - Monday5.) June 30, 2468 - Monday Yeah? No need for the tubes if I'm right. I have no use. Thanks for taking the time to write all this out, pretty cool. Link to comment Share on other sites More sharing options...
Skycastlefish Posted September 17, 2010 Author Share Posted September 17, 2010 (edited) 1.) February 19, 2007 - Monday2.) March 14, 2012 - Wednesday3.) September 1, 1983 - Wednesday4.) July 22, 2222 - Monday5.) June 30, 2468 - Monday Yeah? No need for the tubes if I'm right. I have no use. Thanks for taking the time to write all this out, pretty cool. Some of them are correct. I won't say which ones b/c there are still tubes available for someone else. I was hoping if you won those tubes you would devise some cool project ideas for them, maybe even film them. Since it was your youtube channel that got me into pyro, I was going to send you 15 instead of 5. I hate playing favorites, but I'm in debt to both you and Mumbles. Let me know if you change your mind. Oh yea, if anyone else wants to give it a shot, remember to show your work. Edited September 17, 2010 by Skycastlefish Link to comment Share on other sites More sharing options...
NightHawkInLight Posted September 17, 2010 Share Posted September 17, 2010 (edited) Some of them are correct. I won't say which ones b/c there are still tubes available for someone else. I was hoping if you won those tubes you would devise some cool project ideas for them, maybe even film them. Since it was your youtube channel that got me into pyro, I was going to send you 15 instead of 5. I hate playing favorites, but I'm in debt to both you and Mumbles. Let me know if you change your mind. Oh yea, if anyone else wants to give it a shot, remember to show your work.You're absolutely not in debt to me. I make the videos I do because I enjoy it, and sometimes they do some good. Let me know what ones I got right if they go unanswered for a while. I'm terrible at math, to the point where I often do simple addition and subtraction on my fingers. Totally due to my own laziness in using a calculator for everything no doubt. Edited September 17, 2010 by NightHawkInLight Link to comment Share on other sites More sharing options...
Skycastlefish Posted September 17, 2010 Author Share Posted September 17, 2010 (edited) You're absolutely not in debt to me. I make the videos I do because I enjoy it, and sometimes they do some good. Let me know what ones I got right if they go unanswered for a while. I'm terrible at math, to the point where I often do simple addition and subtraction on my fingers. Totally due to my own laziness in using a calculator for everything no doubt. Sorry, "in debt" is a poor way to say it. I have this thing where I get strong urges to give to people who give to me. Oddly enough, most of the time they don't want it. Hey, nothing wrong with using your hands. I use my hands quite often, especially when multiplying 2 and 3 digit numbers in my head. Heres a good way to count to 99 on two hands. First learn to count to 9 on one hand. 0-9 are counted on your right hand.Its important to start with your thumb, otherwise, your six will look like your three. 0= closed fist1= thumbs up2= thumb and index finger3= thumb, index, and middle finger4= thumb, index, middle, and ring5= all five fingers6= touch the tip of your thumb to your pinky (this sort of looks like how most people make a three)7= tip of thumb to ring finger8= tip of thumb to middle9= tip of thumb to index If you count like this several times you'll find it feels quite natural, almost meant to be. To make two digit numbers, use your left hand for the tens digit, and your right hand for the ones digit.So 15 would be thumbs up on your left and and 5 fingers on your right hand. 76 would be a seven on your left hand (thumb to ring) and a six on your right hand. 40 is four on your left hand, and a fist on your right hand. Pretty cool, huh? Edited September 17, 2010 by Skycastlefish Link to comment Share on other sites More sharing options...
Twotails Posted September 17, 2010 Share Posted September 17, 2010 (edited) 1.) February 19, 2007 monday2.) March 14, 2012 wensday3.) September 1, 1983 thursday4.) July 22, 2222 monday5.) June 30, 2468 saturday Im not quite sure how i did it, it late and my brains all fuzzy. I'll try re-rewiting how i did it in the morning >.< Edited September 17, 2010 by Twotails Link to comment Share on other sites More sharing options...
Skycastlefish Posted September 17, 2010 Author Share Posted September 17, 2010 1.) February 19, 2007 monday2.) March 14, 2012 wensday3.) September 1, 1983 thursday4.) July 22, 2222 monday5.) June 30, 2468 saturday Im not quite sure how i did it, it late and my brains all fuzzy. I'll try re-rewiting how i did it in the morning >.<Bingo! However, how do I know you didn't plug the dates into some internet calender generator? I will make an exception for two reasons. 1. Everyone knows the answers now. 2. You, as i recently learned, see numbers as colors like I do, so I'm almost positive you're good at math. Even if you didn't work them out I bet you could. If you want the tubes they're totally yours. Just send me a pm with where to ship them. Link to comment Share on other sites More sharing options...
Cookieman Posted September 17, 2010 Share Posted September 17, 2010 1.) February 19, 2007 monday2.) March 14, 2012 wensday3.) September 1, 1983 thursday4.) July 22, 2222 monday5.) June 30, 2468 saturday Link to comment Share on other sites More sharing options...
dagabu Posted September 17, 2010 Share Posted September 17, 2010 You guys are incredible!! Really, I mean it! I have to take my shoes off to count to 20. Link to comment Share on other sites More sharing options...
Skycastlefish Posted September 17, 2010 Author Share Posted September 17, 2010 (edited) You guys are incredible!! Really, I mean it! I have to take my shoes off to count to 20. I just updated the above hand counting method from counting to 9 on one hand, to counting to 99 on two hands. Now you can keep your stinky shoes on @Twotails - hey bud, the tubes are in the mail. Enjoy. Edited September 21, 2010 by Skycastlefish Link to comment Share on other sites More sharing options...
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