You can place a formula in one cell (formatted with a Date column type) that adds or subtracts numbers from dates in other cells. Numbers are treated as days, unless date functions are used.
The following table contains examples of using dates in formulas. (The dates in the table below are in mm/dd/yy format.)
|1||5/19/17||=Date1 - 5||Subtracts 5 days from the date||5/14/17|
|2||12/10/17||=Date2 + 5||Adds 5 days to the date||12/15/17|
|3||1/20/18||=DATE(YEAR(date12), MONTH(date12) + 1, DAY(date12))||Add a month to the date with use of the DATE, YEAR, MONTH, and DAY functions||2/20/18|
More information on date functions can be found in the Functions List.
NOTE: You can't place formulas in date columns being used for dependencies. See Enabling Dependencies & Using Predecessors for more on dependencies.