You can use several of the operators with dates and times as summarized here:
Operator | Type of Operation | Result |
Plus | + TimeSpan | TimeSpan |
Negate | - TimeSpan | TimeSpan |
Add | DateTime + TimeSpan | DateTime |
Add | TimeSpan + DateTime | DateTime |
Add | TimeSpan + TimeSpan | TimeSpan |
Subtract | DateTime - DateTime | TimeSpan |
Subtract | DateTime - TimeSpan | DateTime |
Subtract | TimeSpan - TimeSpan | DateTime |
The same order of precedence applies, including use of parentheses, as described in Order of Precedence.
If a DateTime or TimeSpan calculation results in an exception (for example, an OverflowException), the operator returns the #NUM! error.