Line # Field - This field is read-only and is automatically assigned when you save a line in the table. Line # is very important because formulas are always evaluated from the top of the table downward. Lines that reference other variables or calculations need to have a higher line number than the lines they refer to. Generally, variables that users will enter at run time will appear at the top of the table and thus have lower line numbers.
Variable Field - The name of the variable. This can be used to call out the variable on subsequent lines in the formula.
Calculation / Quantity Field - There are three basic options for data in this field. They are:
Empty. The user will be prompted to supply a value at takeoff time.
A number.
A logical expression composed of numbers, mathematical operators, functions, and variables defined previously in the formula. To be called out in an expression a variable must have been defined in a line above the current variable and the variable name must be enclosed in brackets.
