Reverses the value of its argument. Use NOT when you want to make sure a value is not equal to one particular value.
Syntax
NOT(logical)
Logical is a value or expression that can be evaluated to TRUE or FALSE.
Remark
If logical is FALSE, NOT returns TRUE; if logical is TRUE, NOT returns FALSE.
Example
The example may be easier to understand if you copy it to a blank worksheet.
How to copy an example
 Create a blank workbook or worksheet.
 Select the example in the Help topic.
Note Do not select the row or column headers.
Selecting an example from Help
 Press CTRL+C.
 In the worksheet, select cell A1, and press CTRL+V.
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A 
B 
Formula 
Description (Result) 
=NOT(FALSE) 
Reverses FALSE (TRUE) 
=NOT(1+1=2) 
Reverses an equation that evaluates to TRUE (FALSE) 
