Specify the first column or value (Factor1) that will be used in a mathematical expression of:
Factor1 (Operator) Factor2 = Result
The column (real or virtual) must be defined in the physical table, or a valid numeric literal, or an *WORKnnnnn variable.
If a column name has been specified, its data type must be numeric.
This is an optional entry for all operation codes, except for when the operation code of "S" is specified. In this case, the Factor1 field must be blank.