Multiplying Numbers From different tables

     I don't see how the first table is involved in producing the results that you want. It would seem that the data you need for your result is all specified in tables 2 and 3.

     It looks like you need to match records between table 2 and 3 like this:

     Table 3::Area = Table 2::Area AND
     Table 3::Unit = Table 2::Unit

     This assumes that combining the values of Area and Unit in Table 2 produces a value that is unique to only one record in Table 2.

     Then you can reference or copy a price from Table 2 in order to calculate a cost in Table 3:

     Quantity * Table 2::Price

     The relationship controls which record in Table 2 provides the needed price for this calculation.

     Since it looks like "Unit" is the key field between the files you need to create relationships between all of the files using that field.  Once done your calculations should be easy and displaying them in a portal or report also easy. 

     

          The new table has "Unit", "Area 1 Price", "Area 2 Price", "Area 3 Price", and "Area 4 Price". Works perfect now.

     The draw back to that approach is that adding a 5th Area requires a design change to your database. With other methods, the same change is a data entry task--but it would require you to specify the area or area's for which you want prices.