What Does It Do ?This function performs a test to see if the test fails. (A type of reverse logic).
If the test fails, the result is TRUE.
If the test is met, then the result is FALSE.

Syntax
=NOT(TestToPerform)
The TestToPerform can be reference to cells or another calculation.

Formatting
No special formatting is needed.

ExampleThe following table was used by a library to track books borrowed.
The date the book was Taken out is entered.
The period of the Loan is entered.
The date the book was returned is entered.
The =NOT() function has been used to calculate whether the book was returned within
the correct time, by adding the Loan value to the Taken date.
If the book was not returned on time the result Overdue is shown, otherwise OK is shown.