Aviation
For aviation purposes, where it is common to add times in an already complicated environment, time tracking is simplified by recording decimal fractions of hours, so, for instance, if you add 1:36, and 2:36 instead of getting 3:72 and converting it to 4:12 you add 1.6 and 2.6 and get 4.2 hours.
Read more about this topic: Decimal Time