hm(hh;mm) function : Tap once to add "hm(x)" to your device (the function will show in a few seconds under the Custom list)
This will allow to compute hours and minutes this way: hm(1;50) + hm(1;10) ... however, it will always return minutes as a fraction of the hour.
For that, another custom function can be added so that hhmm(1.50) = 1.30 (or 1h30m) and so on : Tap once to add "hhmm(x)" to your device
Please note, both functions must to be used separately since the current release of CALC does not yet support nested custom functions e.g.:
Type: hm(1;30) + hm(1;15) ==> 2.75
Tap equal (=) to store the answer
Utilizing the "ans" button type: hhmm(2.75) ==> this will result in 2.45 (or 2h45m)