you could loop through them...


Code:
Private Sub Text5_KeyPress(keyascii As Integer)

Dim i As Integer
Dim total As Integer

For i = 0 To Text3.UBound
  total = total + Val(Text3(i).Text)
Next

If (Val(Text5.Text) = total) And (keyascii = vbKeyReturn) Then
  Textcorrect.Text = "Correct!"
End If
End Sub