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## Procedure to calculate the day of the week for a given date.

To calculate the day of the week for a given date, first of all we need to find out the number of odd days.

Today I thought of sharing a beautiful problem I learned in my school, though it is easy, it is tricky too.
Odd Days are number of days more than the complete number of weeks in given period.
Leap Year is the year which is divisible by 4.
A normal year has 365 days
A leap year has 366 days
One normal year = 365 days = 52weeks + 1day
One normal year has one odd day

One leap year = 366 days = 52weeks + 2days
One leap year has two odd days

100 years = 76 ordinary years + 24 leap years = 5200 weeks + 124 days = 5217 weeks + 5 days
100 years have 5 odd days

400 years have (20+1) 0 odd days

The number of odd days and the corresponding day of the week is given below

0-Sunday
1-Monday
2-Tuesday
3-Wednesday
4-Thursday
5-Friday
6-Saturday

So by finding out the number of odd days you can find out the day of the week. I hope this procedure Will be helpful in solving math problems in exams.

Thanks.

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