Decrease the value of the variable Name.
The value is decreased by the integer By.
If the variable does not contain a numeric value (e.g. 3) this action will end in error.
If the variable does not exist, it will first be created with a value of 0.
If the Wrap Around parameter is set and the result is below zero, it will wrap back to the Wrap Around value.
See the section on Conditions and Loops in the Userguide for more information.
Use action Variable Set for non-integer subtraction.