This is a chapter upon time calculation. By this, it does not mean that we have to calculate hours and minutes; rather we have to go back some weeks or may be some months and years back to estimate the exact day of some particular event.
This may sound weird at first but once you will go through fundamentals and some examples, you will find this chapter to be very easy. So before going to examples, let’s know some fundamental details those are necessary beforehand.
60 seconds = 1 minute
60 minutes = 1 hour
24 hours = 1 day
7 days = 1 week
4 weeks = 1 month
30 days = 1 month
12 months = 1 year
365 days = 1 ordinary year
366 days = 1 leap year
100 years = 1 century
We have already heard about these but it’s time to recollect them. You must also recollect following things and should keep in mind;
To revolve complete around its axis, earth takes 1 day.
Total time that the earth takes to make a complete revolution around the sun is known as Solar Month and is equals to 365 days 5 hours 48 minutes and 47 1/2 Seconds.
Similarly total time taken by moon to revolve around earth completely is known as Lunar Month and it is nearly equal to 28 days.
Each day is supposed to begin at midnight.
Below are some common terminologies −
| Terminology |
Their Meaning |
| AD |
Anno Domini |
| BC |
Before Christ |
| AM |
Ante Meriden |
| PM |
Post meriden |
The table below describes the common thing that all of us know but it is important in this content to be discussed
| Month Name |
Total num of days |
| January |
31 |
| February |
28 |
| March |
31 |
| April |
30 |
| May |
31 |
| June |
30 |
| July |
31 |
| August |
31 |
| September |
30 |
| October |
31 |
| November |
30 |
| December |
31 |
Leap Year − Those years which are completely divisible by 4 are known as leap years and they contain normally 366 days. Thus years like 2000, 2016, and 1996 are leap years whereas 1997, 2001, 2003 are not.
Some other important notes that you should know −
Before 1 AD there was no 0 AD instead there was 1 BC. Therefore total number of years between a given AD and BC is the addition of two years followed by subtraction with 1.
Weekdays refer to any day in a week except Sunday.
