Today in this post we will cover all the things related to the calendar such as definitions, formulas, examples, and question answers.

Do check out how many weeks in a year article for more amazing formulas.

**Calendar Principles**

Calendars are a means of demonstrating the interrelationships between day, week, month, and year. In other words, we can say that a table representing the month, week, date, and days embodied in a year is called a calendar.

The calendar consists of the following five components.

- Day
- Week
- The date
- Month
- The year

**Day**: – The seventh part of a week is called a day, these are represented by the names of different seven planets.

**Week**: – The fourth or 48th part of a month is called a week, there are a total of seven days in a week of which the first day is Sunday and the last day is Saturday.

**Date**: – The period represented by the digits from 1 to 28/29/30/31 in a month is called date.

**Month**: – Twelfth part of the year is called month, under one year – January, February, March, April, May, June, July, August, September, October, November, and December are 12 months out of which 7 months ( January, March, May, July, August, October and December) are represented by 31 and 4 months (April, June, September, and November) by 30 and the remaining 1 month (February) by 28 or 29 dates.

In the normal year, February is represented by 28 dates, while in the leap year it is represented by 29 dates.

**Year**: – The hundredth part of a century or a combined period of 12 months is called a year, there are two types of years.

1. Normal year

2. leap year

**Normal year**: – The year which is not completely divided by 4 or the centenarian year which is not completely divided by 400, such year is called normal year, any normal year has a total of 365 days.

Such as – 1987, 1989, 1990, 1991 and 1800 here 1800 is a century year.

In a normal year, both the first and last days of the year are the same.

**Leap Year**: – The years which are completely divided by 4 or the centenary years which are completely divided by 400 are called leap years.

Such as 1984, 1988, 1992, 1996 and 2000 here 2000 is a century year.

In the leap year, both the first day and the last day of the year are uneven and the last day is increased by one day as compared to the first day.

**Important Points of Calendar**

Point # 1 – If a year is completely divided by 4, then that year is called a “leap year”. (1 leap year = 366 days)

Point # 2 – If a century is completely divided by 400, then that year is a century leap year.

**Point # 3 **– Number of odd days: –

Sunday – 0

Monday – 1

Tuesday – 2

Wednesday – 3

Thursday – 4

Friday – 5

Saturday – 6

**Point # 4** – There are 12 months in a year, the number of additional days in each month is as follows.

January – 31/7 = 3 additional days

February – (28/7) / (29/7) = 0/1 additional days

March – 31/7 = 3 additional days

April – 30/7 = 2 additional days

May – 31/7 = 3 additional days

June 30/7 = 2 additional days

July – 31/7 = 3 additional days

Aug-31/7 = 3 additional days

September – 30/7 = 2 additional days

October – 31/7 = 3 additional days

November – 30/7 = 2 additional days

December – 31/7 = 3 additional days

**Note** – In a normal year, February is of 28 days, so in a normal year, the number of extra days in February is zero, but in a leap year, Farbari has 29 days, so the number of extra days in February is one.

**Point # 5 **– There are 52 weeks and one day in a year and there are 52 weeks and two days in a leap year.

**Point # 6** – The number of days left by dividing the number by seven is called odd days.

**Point # 7** – A day’s repetition occurs after every 7, 14, 21, 28, ………………, 364 days.

**Point # 8** – The first day of a century can be Monday, Tuesday, Thursday, Friday, or Saturday and the last day of the century cannot be Tuesday, Thursday, or Saturday, but Wednesday, Friday, and Sunday.

**Point # 9** – In an ordinary year, the first days of the following month are the same.

January – October

February – March – November

April – July

September – December

**Point # 10** – The first day of the following month in a half year is the same.

January – April – July

February – August

March – November

September – December

**Point # 11 **– The first and the last days of the practice year are the same.

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**Conclusion**

So, these were some amazing calendar formulas.