Date calculation is also very important for the complex calculation of any manner, date calculation is as important as time calculation and time calculation is related to date calculation. The date is consists of Year, Month and Day. The year consists of 365 days. Year concept is made up with our planet Earth how much time takes to moves around the Sun. It is better to know that, Earth usually takes 365 days 5 hours 45 minutes 46 seconds, but normally year count 365 days and after every four years every fourth year count as Leap year and Leap year consist of 366 days because 5 hours 45 minutes 46 seconds x 4 times = 1 days counts. So, in Leap year 365 + 1 = 366 days and in Leap Year February month counts 29 days instead of 28 days.

OTHER THAN LEAP-YEAR                  LEAP YEAR

JANUARY – 31 Days                    JANUARY – 31 Days

FEBRUARY – 28 Days                   FEBRUARY – 29 Days

MARCH – 31 Days                        MARCH – 31 Days

APRIL – 30 Days                         APRIL – 30 Days

MAY – 31 Days                           MAY – 31 Days

JUNE – 30 Days                          JUNE – 30 Days

JULY – 31 Days                          JULY – 31 Days

AUGUST – 31 Days                      AUGUST – 31 Days

SEPTEMBER – 30 Days                  SEPTEMBER – 30 Days

OCTOBER – 31 Days                     OCTOBER – 31 Days

NOVEMBER – 30 Days                    NOVEMBER – 30 Days

DECEMBER – 31 Days                     DECEMBER – 31 Days

TOTAL – 365 Days                 TOTAL – 366 Days  in Leap Year

Now we will try to understand the addition and subtraction of date through the given example –

Example.1) Find out the days from  12th July to 22nd August

Ans.)  As we know that July month consist of 31 days

So, days remaining in July month = 31 – 12 = 19 days + 1 days ( Because days starting from 12th July, so 1 day is to be count)

=  20 days

And in August month till 22nd August days are = 22 days

So, days between 12th July to 22nd August =  20 + 22 = 42 days (Ans.)

Example.2) Michel’s winter vacation has started 21 days before from 12th February. So, find out his winter vacation starting date.

Ans.)  From 1st February to 12th February = 12 days, so days to be adjusted 21 – 12 = 9 days

So, 9 days to be adjusted from the previous month, that is January and January month of every year consist of 31 days.

Now,  23rd January – 31st January = 9 days

So, Michel’s winter vacation starts on 23rd January.      (Ans.)

Example.3) Mr. Richard and Mrs. Richard went to the UK from the US on 12th May and returned to the US on 5th June. Now calculate how many days they were spent in the UK (consider complete 2days time for up & down transportation has taken) ?

Ans.)  as we know that, May month of every year consists of 31 days.

So, from 12th May there are = (31 – 12 ) + 1 [ 1 day to be added because, 12th May to be count ]

= 19 + 1 = 20 days

And from 1st June to 5th June = 5 days

So, total days = 20 + 5 = 25 days

Exactly they have spent in UK = 25 – 2 = 23 days  [ because as per the given condition, 2 days have waste in transportation ]

So, Mr. Richard and Mrs. Richard were spent a total 23 days in the UK. (Ans.)

Example.4) The college opened 15 days after Devid’s birthday on 22nd February in Leap year. On which day did the collage open?

Ans.) As, we know February month of every leap year consists of 29 days [other than Leap-Year, February consist of 28 days]

So, from 22nd February to 29th February =  8 days  [22nd February itself to be count]

Now, 15 – 8 = 7 days.

So, 7 days to be count from 1st March, then from 1st March to 7th March = 7 days [ 1st day of March to be count]

So, on 7th March college will reopen.   (Ans.)

Example.5) Mr. Archar’s last visit to his office was  8th November, due to his illness he was in bed rest. As per the advice of his doctor he has resumed his duty on 18th December. Now calculate how many days he was on leave?

Ans.) As, we all know November month of every year consists of 30 days.

So, from  8th November to  30th November = (22 +1) days  [8th November to be count]

=  23 days

As per the given condition Mr. Archar resumes his duty on 18th December, so he was on leave till 17th December.

And  1st December to 17th December = (16 + 1) days [ 1st day of December to be count]

=  17 days

So, Mr. Archar total days  he was in leave = 23 + 17 = 40 days.  (Ans.)