Hi I found a neat little way to get the value of an expression using a data table here the code below.
Hope it handy for someone. Comments and suggestions welcome.

vbnet Code:
  1. Option Explicit On
  2.  
  3. Public Class Form1
  4.  
  5.     Private Function EvalIt(ByVal expression As String) As Decimal
  6.         Dim dt As New DataTable()
  7.         Dim RetVal As Decimal = 0
  8.  
  9.         'Check for vaild string
  10.         If Not String.IsNullOrEmpty(expression) Then
  11.             'Use compute to get expression value.
  12.             RetVal = dt.Compute(expression, vbNullString)
  13.         End If
  14.  
  15.         'Return value.
  16.         Return RetVal
  17.  
  18.     End Function
  19.  
  20.     Private Sub cmdGo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdGo.Click
  21.         'Return expresion sum
  22.         Dim buff As String = "5+5 * (10+6) * 2"
  23.  
  24.         MessageBox.Show(buff & "=" & EvalIt(buff), "Eval-Demo",
  25.                         MessageBoxButtons.OK, MessageBoxIcon.Information)
  26.     End Sub
  27. End Class