@arslan_uaf
Subtracting dates is easy: let's say the first date is in A1 and the second date in B1.
In another cell, enter the formula =B1-A1 and format the cell as General.
The cell will display the number of days between the dates.
Adding two dates makes no sense. But you can add a number of days to a date.
Let's say you have a date in A1, and you want to add 7 days to get the date a week later.
Use the formula =A1+7
