There are several add-ins that add new calculation functions to Excel. One of the best is from Charles Williams and FastExcel. The SpeedTools Extras package includes functions that accountants will use in every day work:
- Generate a vector of numbers to be used in amortization tables.
- Return an array of True/False values for each row or column.
- Reverse an array.
- Do wildcard matching with Regular Expressions (RegEx)
- Concatenate a range of text, specifying a delimiter
Check out these tools at http://tinyurl.com/fastexcel.