Finding the difference between 2 times

[erighter]

I am trying to find the difference between 2 times to determine the amount of
time lost between 2 events.

A1: First event ends at 6:00 AM (time format)
A2: Second event begins at 10:00 AM (also time format)

I'd like to express the time lost between those two in hh:mm format.
(A2 - A1)*24 = 20:00 ---> I'd expect 04:00 to show that there's 4 hrs
between.

When A1 = 4:30 AM and A2 = 9:30 AM, the calculation correctly shows 05:00
in time lost.

Where am I going wrong?