Add or subtract hours and minutes
If you have ₹1.50 and you add ₹1.50, you get ₹3.00. But if you have 1 hour and 50 minutes, and you add 1 hour and 50 minutes, you do not get 3 hours. You get 3 hours and 40 minutes!
This confusion happens because most human math is Base-10 (Decimal), where a column carries over when it hits 10 or 100. But time is calculated in Base-60 (Sexagesimal), a mathematical system inherited from the ancient Sumerians over 4,000 years ago.
To do math on time, computers completely ignore the concepts of "hours" and "minutes". They convert everything down to the smallest possible uniform unit (usually milliseconds or seconds), perform standard Base-10 math on that massive number, and then parse it back into Base-60 for the human UI.
To mathematically add 1h 50m and 1h 50m:
Step 4 relies on the Modulo (%) operator. Instead of giving the result of division, Modulo returns the remainder of a division. 220 % 60 asks the computer: "If I divide 220 by 60 into whole numbers, what is left over?" The answer is 40. This is exactly how this tool flawlessly adds and subtracts hours, minutes, and seconds.
Why can't you just add 1.50 (representing 1h 50m) and 1.50 on a standard desktop calculator to get time addition?
