7days 4 hours – 4 days 7 hours = days hours

Let's put this into only hours to make it simple.
Multiply 7 and 4 by 24.
7x24 = 168
4x24 = 96
Now that we have the total hours of days, add the extra hours to the total hours of days,
168 + 4 = 172
96 + 7 = 103
Subtract the two totals.
172-103 = 69.
There are 69 total hours left. Now we need to convert that into days and hours, so divide 69 by 24.
69/24 = 2.875, or 2 days.
We have 2 days, which is 48 hours.
Subtract 48 from 69.
69 - 48 = 21. We have 21 hours.
Our difference is 2 days and 21 hours. I hope this helps!