主窗体：
Private Sub 折让_DblClick(Cancel As Integer)
    '请在OpenArgs参数中，用,号分割主窗体、子窗体控件、控件名称
    Dim Ctlname As String
    Ctlname = Screen.ActiveControl.Name
    DoCmd.OpenForm "myCalc", , , , , , Me.Form.Name & "," & Ctlname
End Sub
子窗体：
Private Sub 数量_DblClick(Cancel As Integer)
    '请在OpenArgs参数中，用,号分割主窗体、子窗体控件、控件名称
    Dim Ctlname As String
    Ctlname = Screen.ActiveControl.Name
    DoCmd.OpenForm "myCalc", , , , , , Me.Parent.Form.Name & "," & Me.Form.Name & "," & Ctlname
End Sub
myCalc窗体：
Private Sub 等于_Click()
Dim str As String
Dim Pfname As String
Dim Sfname As String
Dim Cname As String
On Error GoTo 等于_Err
    If IsNull(Me.计算.Value) = False Then
        Me.计算.Value = Eval(Me.计算.Value)
    Else
         Me.计算.SetFocus
        Exit Sub
    End If
    If OpenArgs <> "" Then
        str = OpenArgs
        Pfname = Mid(str, 1, InStr(1, str, ",") - 1)
        str = Replace(str, Pfname & ",", "")
        If InStr(1, str, ",") = 0 Then
            Sfname = Pfname
            Cname = str
            Forms(Sfname).Form.Controls(Cname).Value = Me.计算.Value
        Else
            Sfname = Mid(str, 1, InStr(1, str, ",") - 1)
            str = Replace(str, Sfname & ",", "")
            Cname = str
            Forms(Pfname).Controls(Sfname).Form.Controls(Cname).Value = Me.计算.Value
        End If
        DoCmd.Close acForm, "myCalc"
    End If
等于_Exit:
    Exit Sub
等于_Err:
    Me.计算.Value = "兄弟，搞错了吧？！^o^  "
    Resume 等于_Exit
End Sub
Private Sub L0_Click()
    Me.计算.Value = Me.计算.Value & Me.L0.Caption
End Sub
。。。。。