Código
Public Class Form1 Dim OP As String Dim a, b, resultado As Double Dim c As Double Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load End Sub Private Sub Button11_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button11.Click If c = True Then Text1.Text = "" End If Text1.Text = Text1.Text + "2" c = False End Sub Private Sub Button9_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button9.Click If c = True Then Text1.Text = "" End If Text1.Text = Text1.Text + "3" c = False End Sub Private Sub Button8_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button8.Click If c = True Then Text1.Text = "" End If Text1.Text = Text1.Text + "4" c = False End Sub Private Sub Button7_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button7.Click If c = True Then Text1.Text = "" End If Text1.Text = Text1.Text + "5" c = False End Sub Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click If c = True Then Text1.Text = "" End If Text1.Text = Text1.Text + "6" c = False End Sub Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click If c = True Then Text1.Text = "" End If Text1.Text = Text1.Text + "7" c = False End Sub Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click If c = True Then Text1.Text = "" End If Text1.Text = Text1.Text + "8" c = False End Sub Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click If c = True Then Text1.Text = "" End If Text1.Text = Text1.Text + "9" c = False End Sub Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click If c = True Then Text1.Text = "" End If Text1.Text = Text1.Text + "0" c = False End Sub Private Sub Button17_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button17.Click Text1.Text = Text1.Text + "." End Sub Private Sub Button12_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button12.Click a = Text1.Text Text1.Text = "" OP = "SUMA" End Sub Private Sub Button15_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button15.Click a = Text1.Text Text1.Text = "" OP = "RESTA" End Sub Private Sub Button14_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button14.Click a = Text1.Text Text1.Text = "" OP = "MULTIPLICACION" End Sub Private Sub Button13_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button13.Click a = Text1.Text Text1.Text = "" OP = "DIVISION" End Sub Private Sub Button16_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button16.Click b = Val(Text1.Text) Select Case OP Case "SUMA" resultado = a + b Text1.Text = resultado Case "RESTA" resultado = a - b Text1.Text = resultado Case "DIVISION" resultado = a / b Text1.Text = resultado Case "MULTIPLICACION" resultado = a * b Text1.Text = resultado End Select End Sub End Class