Addition of Hours, Minutes and Seconds

We will discuss here about the addition of hours, minutes and seconds.
Let us consider some of the examples on adding time.

Let us consider some examples:

1. Add 3 hr. 25 min. 15 sec. and 5 hr. 20 min. 25 sec.

 We added hours, minutes and seconds respectively.

2. Add 5 hr. 45 min. 12 sec. and 7 hr. 50 min. 24 sec.

 = 12 hr. 1 hr. + 35 min. + 36 sec. = 13 hr. 35 min. 36 sec. 12 hr. 95 min. 36 sec. = 12 hr. + (60 min. + 35 min.) + 36 sec. = 12 hr. 1 hr. + 35 min. + 36 sec. = 13 hr. 35 min. 36 sec.

3. Add 30 hr. 45 min. 45 sec. and 15 hr. 35 min. 17 sec.

 = 45 hr. 1 hr. 20 min.  1 min. 11 sec. = 46 hr. 21 min. 11 sec. 45 hr. 80 min. 71 sec. = 45 hr. + (60 min. + 20 min.) + (60 sec. + 11 sec.) = 45 hr. + 1 hr. + 20 min. + 1 min. + 11 sec. = 46 hr. 21 min. 11 sec.

4. Add 24 hr. 30 min. 20 sec. and 18 hr. 37 min. 54 sec.

 = 42 hr. 1 hr. 7 min. 1 min. 14 sec. = 43 hr. 8 min. 14 sec. 42 hr. 67 min. 74 sec. = 42 hr. + (60 min. + 7 min.) + (60 sec. + 14 sec.) = 42 hr. + 1 hr. + 7 min. + 1 min. + 11 sec. + 14 sec. = 43 hr. 8 min. 14 sec.

4th Grade Math Activities

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