This is for calculating time and angle.

For example, you can calculate
1hr 30min + 3hr 45min = ?
1hr / 100 = ?
How many hours and minutes are 10000 seconds?

This app will also help calculation for the horoscope, as follows
360° / 24 = ?
15° 30' - 5° 45' = ?

The system is very simple.
you just choose [time/angle] mode and [+,-,x,/] mode and input numbers.