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 CALENDAR :-
Choose Your Formula/Rule for quicker method
 IMPORTANT EXAMPLES
 ::Important Formulas ::Important Examples .

Here Some Basic Formulas/Rules Are given below :-

We are supposed to find the day of the week on a given date.
For this, we use the concept of odd days.
1. Odd Days : In a given period, che number of days more than the complete weeks are called odd days.

2. Leap Year :
1.Every year divisible by 4 is a leap year, if it is not a century.
2.Every 4th century is a leap year and no other century is a leap year.
Note : A leap year has 366 days.
Examples :
1. Each of the years 1948, 2004, 1676 etc. is a leap year.
2. Each of the years 400, 800, 1200, 1600, 2000 etc. is a leap year.
3. None of the years 2001, 2002, 2003, 2005, 1800, 2100 is a leap year.

3. Ordinary Year :
The year which is not a leap year is called an ordinary year. An ordinary year has 365 days.

4. Counting of Odd Days :
1. 1 ordinary year = 365 days = (52 weeks + 1 day).
So 1 ordinary year has 1 odd day.
2. 1 leap year = 366 days =(52 weeks + 2 days).
So 1 leap year has 2 odd days.
3. 100 years = 76 ordinary years + 24 leap years.
= (76 X 1 + 24 X 2) odd days = 124 odd days
= (17 weeks + 5 days) = 5 odd days.
Number of odd days in 100 years = 5
Number of odd days in 200 years = (5 x 2) = 3 odd days
Number of odd days in 300 years = (5 x 3)a-- 1 odd day.
Number of odd days in 400 years = (5 x 4 + 1) 0 odd day.
Similarly, each one of 800 years, 1200 years, 1600 years, 2000 years etc.
has 0 odd day.

5. Day of the Week Related to Odd Days :

 No. of days 0 1 2 3 4 5 6 Day Sun. Mon. Tues. Wed. Thurs. Fri. Sat.