1:30 (hours:minutes) or
1.5 (with a period) or
1,5 (with a comma)

for 1 hour and 30 minutes.

0:00 or a blank field

creates a time entry with a running timer.

8 to 13:30 or 8 13:30 or 8am 1:30pm

for a time frame from 8:00 to 13:30.

The specified starting time and ending time will be saved as a note.

8 to 8 oder 8 8

creates a time entry with a running timer, starting at 8:00. The ending time will increment automatically.

2+0:15

for 2 hours plus 15 minutes.

2-0:15

for 2 hours minus 15 minutes.

2*1.5

for 2 hours multiplied by 1.5, aka 3 hours.

3/1.5

for 3 hours divided by 1.5, aka 2 hours.