How you can mathematically calculated that what is the day today as 06 april,2018 ?
Answers
The formula is:
(Year Code + Month Code + Century Code + Date Number – Leap Year Code) mod 7
Here’s How it WorksI’ll run through an example with the date, 14 March 1897 — Einstein’s birthday.
The Year CodeTo calculate the Year Code, use this formula:
(YY + (YY div 4)) mod 7
YY is the last two digits of the year. For the year 1897, it’s 97.
First, divide YY by 4 and discard the remainder: 97 div 4 = 24.
Then add 24 back into the YY number, which is 97 in this case, resulting in 121.
The next step is: 121 mod 7.
“Mod” means to divide the number and keep only the remainder. For 121 mod 7, start removing sevens:
10 x 7 is 70, leaving us with 51, because 121 – 70 = 51.7 x 7 = 49, and 51 – 49 = 2.We’ve removed all the sevens from 121 until we are left with a remainder of 2. That is the Year Code for 1897.
You could use a number shape image like a swan to hold that in memory while you calculate the items below.
The Month CodeThis is easy — just memorize the number 033614625035:
January = 0February = 3March = 3April = 6May = 1June = 4July = 6August = 2September = 5October = 0November = 3December = 5Now you have the Month Code. For Einsteins birthday in March, it is 3.
A Quick Note on Memorizing NumbersIf you don’t know how to memorize a number like 033614625035, you could either use repetition or learn a mnemonic system like the Major System or Dominic System. I use my Ben System images: Samwise (033) throws a glass of beer (614) on George Boole (625) who falls backwards on Sally (035).
A way to quickly memorize 033614625035 without a complex mnemonic system would be to use a number shape system to associate images with each month. For example, you could picture a game of soccer (football) in January, with ball being a mnemonic image for zero. You could picture a butterfly in February and March, if you use a butterfly image for the number three. If the number six is represented by the image of an elephant, picture an elephant in April and July, and so on. If you are having trouble associating the images with the months, pick an aspect of each month to associate the image with. For example, Halloween is in October, so to remember that October has a Month Code of zero (represented by an image of a ball), you could picture a group of people in Halloween costumes doing something with a ball. That would link the month of October with the number zero.
The other thing to take into account is whether you are dealing with a leap year. EDIT: If the date is in a January or February of a leap year, you have to subtract one from your total before the final step.
If you can divide a Gregorian year by 4, it’s a leap year, unless it’s divisible by 100. But it is a leap year if it’s divisible by 400.
1992 is a leap year because you can divide it by four.
1900 is not a leap year because you can divide it by 100.
2000 is a leap year because you can divide it by 400.
If you can divide a Julian year by 4, it’s a leap year.
Einstein’s birthday was in 1897 which was not a leap year (0), so it doesn’t affect the outcome.
Calculating the Day
Back to the original formula:
(Year Code + Month Code + Century Code + Date Number – Leap Year Code) mod 7
Year Code: 2Month Code: 3Century Code: 2Date Number: 14 (the 14th of the month)Leap Year Code: 0
So:
(2 + 3 + 2 + 14) mod 7 = 21 mod 7 = 0
Match the resulting number in the list below, and you’ll have the day of the week:
0 = Sunday1 = Monday2 = Tuesday3 = Wednesday4 = Thursday5 = Friday6 = Saturday
Einstein was born on a Sunday.
Here are three more examples from different centuries:
Humans set foot on the moon: 20 July 1969:
Take ’69 and divide by 4, discarding the remainder. That leaves 17. Add 69 to 17 to get 86. Then, 86 mod 7 = 2. The Year Code is 2.The Month Code for July is 6.The Century Code for the 1900s is zero.The Date Number is 20, because it’s the 20th of July.1969 wasn’t a leap year since it can’t be divided by 4.2 + 6 + 0 + 20 = 2828 mod 7 = 0
20 July 1969 was a Sunday.
The Battle of Hastings took place on 14 October 1066.
Take ’66 and divide by 4, ignoring the remainder: 16. Add 66 to 16 to make 82. 82 mod 7 makes a Year Code of 5.October has a Month Code of zero.The Day Number is 14.The Century Code for this Julian date is 18 – 10 = 8. 8 mod 7 = 1.1066 was not a leap year.Answer: 5 + 0 + 14 + 1 = 20. 20 mod 7 = 6
14 October 1066 was a Saturday.
1 January 2000:
Start with ’00, leaving a Year Code of zero.January has a Month Code of zero.The Day Number is 1.The Century Code for dates in the 2000s is 6.2000 is a leap year, since it can be divided by 400, and the date is in a January or February, so subtract 1 from the total in the final step.Answer: 0 + 0 + 1 + 6 – 1 = 6.
1 January 2000 was a Saturday.
Hope This Helps :)
Example 2: if the year is 1625 CE, take the century number, 16, and subtract it from 18, leaving 2. 2 mod 7 = 2, so in this case the Century Code is 2.
For Einsteins birthday in 1897, the Century Code is 2, because it’s a Gregorian date, and the chart above shows that dates in the 1800s get an adjustment of 2.