Private Sub RuaCommand_Click()
Dim Number1 As Single, Number2 As Single, Result As Single

Number1 = Val(InputText1)
Number2 = Val(InputText2)

If AddOption = True Then
Result = Number1 + Number2
End If
OutputText.Text = Result
End Sub
以上是我的代码。输入1+1居然=0
1+2一样=0。
爆汗

......

AddOption = True,我就没明白过,这句话是什么意思

为什么要这句“If AddOption = True Then”？

就算要，也应该：
If AddOption = True Then
   Number1 = Val(InputText1)
   Number2 = Val(InputText2)

   Result = Number1 + Number2
   OutputText.Text = Result
End If