Using numbers and dates in an expression
When you create an expression that contains a literal number, you must type the number according to the conventions of the US English locale. In other words, use a period (.), not a comma (,) as the decimal separator, even if you are working in, for example, the French locale. For example:
Correct: ([Quantity] * [Price]) * 1.5
Incorrect: ([Quantity] * [Price]) * 1,5
Similarly, when you create an expression that contains a literal date, type the date according to the conventions of the US English locale. For example, if you are working in the French locale, type 03/12/2007 to represent March 12, 2007. Do not type 12/03/2007, which is the convention for the French locale. You must enclose literal date values in double quotation marks (" "), as shown in the following expression, which calculates the number of days from the order date to Christmas:
DIFF_DAY([OrderDate], "12/25/08")

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