做一个按钮
Private Sub Command1_Click()
a = 299
For i = 2 To Sqr(299)
  If 299 Mod i = 0 Then
     MsgBox "299=" & i & "*" & 299 / i
    i = 299
  End If
Next i
End Sub

你点一下按钮，看到了什么？仔细看看你就会明白