You can prevent users from entering incorrect values.
In the example below, cascading Excel formulas are used to build a logic preventing the user from entering negative values for revenue accounts:
$G$5 counts the number of negative values.
$H$5 returns FALSE if there is at least one negative value, TRUE otherwise.
and $I$5 contains the message that is displayed if $H$5 returns FALSE.
The Validation check is set to cell $F$5 and the Validation message is set to $9$5 on the Writeback tab of the Workbook Options window.
