this works with 4 textboxes + 4 checkboxes
(named textbox1, textbox2, checkbox1, checkbox2, etc)

vb Code:
  1. Private Sub TextBoxes_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) _
  2.     Handles TextBox1.TextChanged, TextBox2.TextChanged, TextBox3.TextChanged, TextBox4.TextChanged
  3.     doTotal()
  4. End Sub
  5.  
  6. Private Sub CheckBoxes_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) _
  7.     Handles CheckBox1.CheckedChanged, CheckBox2.CheckedChanged, CheckBox3.CheckedChanged, CheckBox4.CheckedChanged
  8.     doTotal()
  9. End Sub
  10.  
  11. Private Sub doTotal()
  12.     Dim total As Decimal = 0
  13.     For x As Integer = 1 To 4
  14.         If DirectCast(Me.Controls("checkbox" & x), CheckBox).Checked Then
  15.             total += CDec(Val(DirectCast(Me.Controls("textbox" & x), TextBox).Text))
  16.         Else
  17.             total -= CDec(Val(DirectCast(Me.Controls("textbox" & x), TextBox).Text))
  18.         End If
  19.     Next
  20.     Label1.Text = CStr(total)
  21. End Sub

you'd have to modify the handles statements in TextBoxes_TextChanged + CheckBoxes_CheckedChanged to include 14 textboxes + checkboxes