### Online Exam » Aptitude » Calenders

**Calenders :**

Calender helps us in finding the day of the week for a particular date. In order to find the day of the week, we calculate the number of odd days during that particular period. The number of days more than the complete number of weeks in a given period, are called odd days.

**Solar year :** The time taken by the earth to make one complete revolution around the sun and is equivalent to 365 days, 5 hours, 48 min. and 47 ½ sec.

**Leap year :** Every year which is divisible by 4 is called a leap year. In a leap year there are 29 days for the month of Feburary.

Leap year = 366 days = 52 weeks + 2 days

Non leap year = 365 days = 52 weeks + 1 day

An ordinary year has 1 odd day and a leap year has 2 odd days

400 solar years = 400 calender years

= 97 leap years + 303 non leap years

100 years gives 5 odd days

200 years gives 3 odd days

300 years gives 1 odd day

400 years gives 0 odd day

We count days according to number of odd days.

Sunday for 0 odd day, Monday for 1 odd day and so on**.**