Expression Help? (Algebra is FUN!)

[carrybag93]

I have a table with the fields 'Weight (kg)', 'State/Territory', 'Cost per Kilogram' and 'Postage Cost'. It depends on which state they want to send their item to as to the cost per kilogram. I would like to make this table into a form where:
1. The user inputs the weight into a text box.
2. The user selects the state from a combo box.
3. The cost per kilogram doesn't show.


4. In a box at the bottom, the total cost of postage is displayed. This should be automatically calculated, which will be the weight * cost per kilogram.

It is important that the weight per kilogram isn't shown, and this is selected by the user choosing a state to send their item to.

Any help would be greatly appreciated!!

[R_Badger]

I need to understand your table structure better, the Weight (kg) field seems redundant in a table containing the pricing details, unless there is a weight bracket differential in which case you should really have min_weight and max_weight.
I also feel the need to say spaces and special characters really should be omitted from field names.

However what you want to do sounds easy enough with a better understanding of the data structure.