Add times
The same key works for hours, minutes and seconds. Type 3, press 
, type 30, press , type 45, and press 
. Type 6, press , type 45, press , type 36, and press 
: 3 hours 30 minutes 45 seconds plus 6 hours 45 minutes 36 seconds is 10°16'21", that is 10 hours, 16 minutes and 21 seconds.