How to do many many calculations

Hi we are converting an excel app. We will have a Projects table with 5 projects. There will be about 10 tables that have lots of calculations. There are about 300 variables that the user enters, and are used variously throughout the calculations. Im wondering how to organize the variables and calculations.  I could add all variables as fields in the project table and link the tables or use query functions to use them in calcs.  OR I could have a variables table, with a record for variable name and value, but not sure this works for the calculation field (diff formula for each record?). 

Any ideas how to handle this?