This is a simple time management system of the day.
The user enters the start and end time.
These are within 24 hours.
You will be able to know the number of seconds remaining until the end time.
And you can see at a glance what percent advanced.
Example of use:
When you feel bored with university lectures you, if you look at the rest of the time.
If you want to leave early work in spare time, counting down to open the iPhone secretly.