Math formula's can be made for Contacts, Companies, Groups, Opportunities, Opportunity Products or Custom Tables.  They can be used to add sets of numbers together, concatenate characters, compare dates among other uses.  Math formula's are run when one of the fields involved in the formula is tabbed through.  On a custom table the all the math formula's can be run by clicking the run all math button  in the toolbar.

Math formula's can be accessed by the math settings, also if the formula is for a custom table or opportunity product through the Form Designer.

Impact suite support all the financial functions in the Microsoft Financial class as described here:
http://msdn.microsoft.com/en-us/library/microsoft.visualbasic.financial(v=vs.110).aspx

Creating Math Formulas

Editing Math Formulas

Math Syntax

Summing Up Parent Table

Summing Up Child Tables

Summing Between Tables

Column Totals

Financial Functions

See also