## Bhavuk Pujara is teaching live on Unacademy Plus

FEBRUARY 2016 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 CALENDARS Concept

CALENDAR years Ordinary year - An ordinary year has 365 days Leap vear - A leap year has 366 days ' Difference between an ordinary year & a leap year is that a leap year has an extra day, as 29th Feb.

CALENDAR years Leap year occurs every 4 years, to keep the calendar in alignment with the earth's revolution around the sun Earth takes 365 1/4th day or 6 hours in the calendar there is a leap year days to complete 1 revolution, thus to compensate . A year is NOT a leap year if it's not divisible by 4 or 400 Example: Years 1600, 2400 are divisible by 400, thus Leap years & Years 1700, 2100, 2300 are NOT divisible by 400, thus not Leap years

Odd days Odd days - In a given time period, the no. of days that are more than the weekly cycle are called Odd days Example: In 12 days, we have 1 week & 5 days There are 5 Odd days In 23 days, we have 3 weeks & 2 days > There are 2 Odd days In 70 days, we have 10 weeks & 0 days There are 0 Odd days

Odd days Example: In an Ordinary year, we have 52 weeks & 1 day There are 1 Odd day in 1 Ordinary year In a Leap year, we have 52 weeks & 2 days There are 2 Odd days in 1 Leap year Therefore, an Ordinary year has 1 Odd day & a Leap year has 2 Odd days

Reference Chart January 1st 0001 A. D, was a Monday (Reference Chart) Reference Chart Number of Odd days 0 Day of the week Sunday Monday Tuesday Wednesday Thursday Friday Saturday 2 3 4 **Sunday is taken as the Reference point

CALENDAR Problem types Type 1. Find the day of the week for a given date when some other date & day is specified Reference gi ven Type 2. Find the day of the week for a given date when NO other date & day is specified No reference given