The addition of time or time addition is very much important to calculate the complex calculations of science.

Example.1)  Add 8 hours 15 minutes and  2 hours 25 minutes

Ans.)               8 hours   15 minutes

+       2 hours   25 minutes

----------------------------

10 hours  40 minutes

(In this case add hours and minutes separately)      (Ans.)

Example.2)  Add 7 hours 42 minutes and 4 hours 63 minutes

Ans.)               7 hours   42 minutes

+       4 hours   63 minutes

------------------------------

11 hours  105 minutes

(In this case add hours and minutes separately)

From the above addition we can find 105 minutes, we can describe or regroup like that 105 minutes = (60 + 45) minutes. As we all know that, 60 minutes = 1 hour, so add 1 hour with 11 hours and put 45 minutes at minute place.

So, 11 hours 105 minutes = 12 hours 45 minutes.        (Ans.)

Example.3) Add 5 hours 35 minutes 45 seconds and  4 hours 45 minutes 42 seconds

Ans.)               5 hours   35 minutes   45 seconds

+    4 hours   45 minutes   42 seconds

-----------------------------------

9 hours   80 minutes   87 seconds

(In this case add hours, minutes, and seconds separately)

From the above addition we can find 87 seconds, we can describe or regroup like that 87 seconds = (60 + 27) seconds. As we all know that, 60 seconds = 1 minute, so add 1 minute with 80 minutes and put 27 seconds at seconds place.

Now, we have 81 minutes, we can describe or regroup like that 81 minutes = (60 + 21) minutes. As we all know that, 60 minutes = 1 hour, now add 1 hour with 9 hours and put 21 minutes at minute place.

So, 9 hours 80 minutes 87 seconds = 10 hours 21 minutes 27 seconds. (Ans.)