Option Compare Database
Dim anterior As Double
Dim signo As Double
Private Function suma(Numero As Double, Operador As Double) As Double
suma = Numero + Operador
End Function

Private Function resta(Numero As Double, Operador As Double) As Double
resta = Numero - Operador
End Function
Private Function multiplicar(Numero As Double, Operador As Double) As Double
multiplicar = Numero * Operador
End Function
Private Function dividir(Numero As Double, Operador As Double) As Double
dividir = Numero / Operador
End Function


Private Function decimal(Numero As Double, Operador As Double) As Double
decimal =
End Function

Private Sub cmd0_Click()
txtDisplay.Value = txtDisplay.Value + "0"
End Sub

Private Sub cmd1_Click()
txtDisplay.Value = txtDisplay.Value + "1"
End Sub

Private Sub cmd2_Click()
txtDisplay.Value = txtDisplay.Value + "2"
End Sub

Private Sub cmd3_Click()
txtDisplay.Value = txtDisplay.Value + "3"
End Sub

Private Sub cmd4_Click()
txtDisplay.Value = txtDisplay.Value + "4"
End Sub

Private Sub cmd5_Click()
txtDisplay.Value = txtDisplay.Value + "5"
End Sub

Private Sub cmd6_Click()
txtDisplay.Value = txtDisplay.Value + "6"
End Sub

Private Sub cmd7_Click()
txtDisplay.Value = txtDisplay.Value + "7"
End Sub

Private Sub cmd8_Click()
txtDisplay.Value = txtDisplay.Value + "8"
End Sub

Private Sub cmd9_Click()
txtDisplay.Value = txtDisplay.Value + "9"
End Sub

Private Sub CmdCa_Click()
txtDisplay.Value = ""
End Sub

Private Sub cmdClear_Click()
txtDisplay.Value = ""
End Sub

Private Sub cmdDivide_Click()
signo = 3
anterior = Val(txtDisplay.Value)
txtDisplay.Value = ""

End Sub

Private Sub cmdEquals_Click()
Select Case signo 'la variable signo te dice si sumas(0) si restas(1)......
Case 0
txtDisplay.Value = suma(anterior, Val(txtDisplay.Value)) 'llamada a la función suma
Case 1
txtDisplay.Value = resta(anterior, Val(txtDisplay.Value))
Case 2
txtDisplay.Value = multiplicar(anterior, Val(txtDisplay.Value)) 'llamada a la funcion multiplicar
Case 3
txtDisplay.Value = dividir(anterior, Val(txtDisplay.Value)) 'llamada a la funcion dividir
Case 4
txtDisplay.Value



End Select
End Sub

Private Sub cmdMinus_Click()
signo = 1 'si index es 0 sumas, si es 1 restas......
anterior = Val(txtDisplay.Value)
txtDisplay.Value = ""
End Sub

Private Sub cmdMultiply_Click()
signo = 2
anterior = Val(txtDisplay.Value)
txtDisplay.Value = ""

End Sub

Private Sub cmdPlus_Click()
signo = 0 'si index es 0 sumas, si es 1 restas......
anterior = Val(txtDisplay.Value)
txtDisplay.Value = ""
End Sub

Private Sub Detalle_Paint()
If IsNull(txtDisplay.Value) Then
txtDisplay.Value = ""
End If
End Sub

Private Sub cmdDP_Click() 'coma del numero

txtDisplay.Value = txtDisplay.Value + ","


End Sub
Private Sub Form_Current()

End Sub

Hola, tengo la extraña sensación de que esto no es VB6, sino que mas bien es 2008, de todos modos, tal vez deberías probar a indicar que se trata de un (.) decimal en lugar de la coma (,), tal vez por ahí esté el problema.

En VB6 Val("12.22") es igual a 12,22 mientras que Val("12,22") es igual a 12

Saludos