Ahhhhh! I got it! Sort of...well, okay, it is a work-around anyway.

Imports System

Imports System.Data

Imports System.Data.SqlClient

Imports System.Data.SqlTypes

Imports Microsoft.SqlServer.Server

Imports Microsoft.VisualBasic.Strings

Partial Public Class UserDefinedFunctions

<Microsoft.SqlServer.Server.SqlFunction()> _

Public Shared Function stringEval(ByVal equation As String) As SqlString

Dim table As New DataTable

Dim eqObject As Object

eqObject = table.Compute(equation, "")

Dim results As SqlString = SqlDecimal.Parse(eqObject.ToString()).ToString()

Return results

End Function

End Class

I'm sure someone can figure this out, but it actually works better than I had originally thought as is. To use it, I simply call it as

select ..., convert(decimal(18,2), dbo.stringEval(stringWithMathEquation)) ...

In case anyone uses this, or wants to tweak it, I can only get it to work by either using the string that it returns, or to use a convert or cast to decimal. It gets an error if I try to convert/cast it directly to an int. I'm not sure what all of the issues are, but it at least gives me a short-term fix and the result can then be managed with native SQL functions to change it to any other datatype.

Thank you!