FIND THE DAY ON A PARTICULAR DATE

Most of the times,  you will be finding the day in 19th ,20th or 21st century.

So, remember, 19th century started with a sunday(january 1, 1800 was a sunday), 20th century with first working day i.e. monday(january 1, 1900 was a monday).

so if the concerned date is in 19th century. take 1 jan, 1800(sunday) as a reference. else if it is after 19th century, take 1 jan, 1900(monday)as a reference.

the scale i used is 0-6(i.e. if friday is 0 then saturday will be 1, sunday will be 2 and so on till thursday will be 6).

Main Method():

lets discuss this method with a date say (3 april 1990)

Take the reference as described above.

1. now you know first day of the century. so now you can find the first day of any year lies within that century.

in our example. 1 january 1990 can be calculated as:

* remember the word LID or DIL(hindi for Heart) whatever suites you.

L: leap years between the year concerned(not included) and reference year(included).
I: I symbolises 1
D: difference between the year concerned and reference year.

add these and divide by 7. the remainder is the day of the year with respect to the reference year.

(here, there are 21 leap years between 1990 and 1900   +   1   +   the difference is 90).
it comes out to be 112
divide this number by 7 that is 112/7 = 0 is the remainder.



So, 1 january 1990 is monday(1 january 1900)+0(remainder)= monday.

2. now to calculate first day of the concerned month of the concerned year.
remember a number series, i.e.

358-0-358-1-368

as 1 January of the year concerned is known, the day at any date of the January can be calculated easily(no need to tell). so , the series above starts with the month February.

one more thing, the number in the series represents the following number from February to December respectively.
3 - 3
5 - 5
8 - 8
0- 10
3- 13
5- 15
8- 18
1- 21
3- 23
6- 26
8- 28
(because, it is easy to learn single digits than double digits, obviously).

now to calculate concerned month
(deduct two from the month code above(if its not a leap year) else 1).
and divide the outcome by 7 and remainder is the first day of that month. with respect to 1 January of that year.
never deduct anything from February code as leap year does not affect first date of February (1 Feb. comes before 29 February).


in our example, April is the month so deduct 2 from 8(as 1990 is not a leap year) i.e. 6 and divide the 6 by 7  which gives the remainder 6.

hence first day of April is [Monday(1 January 1990) + 6(remainder)] = Sunday

which gives third April as Tuesday.

so two things to remeber are:

1. LID
2. 358-0358-1-368
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lets discuss one more problem:

8 November 1992(leap year).
applying  LID to 1992:
21 +1 + 92 =114/7 = (16+2) = 2 is the remainder

so the first day of 1992 is Moday(1 January 1900) + 2 = Wednesday


now to find the first day of November of the year 1992.

apply the number series.
November's code is 26
so deduct 1 from 26 (as 1992 is a leap year) and divide the outcome by 7
so 25/7 = 4 is the remainder.
so first day of November is Wednesday + 4 = Sunday
so , 8th of November, 1992 is also Sunday.
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believe me, it just looks like a long method, actually if you practice it few times, it just comes down to two or three things.


Thank you,

hope it helps,

leave your feedback in the comment. I would appreciate it.