.NET How to make a calculator with 1-9, +,-,*,/, and Clear buttons. Source. and Video Tut

Code
Public Class Form2

    Dim FirstNumber As Long

    Dim Operation As String

    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load



    End Sub



    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        TextBox1.Text = TextBox1.Text & 1

    End Sub



    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

        TextBox1.Text = TextBox1.Text & 2

    End Sub



    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click

        TextBox1.Text = TextBox1.Text & 3

    End Sub



    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click

        TextBox1.Text = TextBox1.Text & 4

    End Sub



    Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click

        TextBox1.Text = TextBox1.Text & 5

    End Sub



    Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click

        TextBox1.Text = TextBox1.Text & 6

    End Sub



    Private Sub Button7_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button7.Click

        TextBox1.Text = TextBox1.Text & 7

    End Sub



    Private Sub Button8_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button8.Click

        TextBox1.Text = TextBox1.Text & 8

    End Sub



    Private Sub Button9_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button9.Click

        TextBox1.Text = TextBox1.Text & 9

    End Sub



    Private Sub Button15_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button15.Click

        TextBox1.Text = TextBox1.Text & 0

    End Sub



    Private Sub Button10_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button10.Click

        FirstNumber = TextBox1.Text

        TextBox1.Text = ""

        Operation = "+"

    End Sub



    Private Sub Button12_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button12.Click

        FirstNumber = TextBox1.Text

        TextBox1.Text = ""

        Operation = "-"

    End Sub



    Private Sub Button11_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button11.Click

        FirstNumber = TextBox1.Text

        TextBox1.Text = ""

        Operation = "*"

    End Sub



    Private Sub Button13_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button13.Click

        FirstNumber = TextBox1.Text

        TextBox1.Text = ""

        Operation = "/"

    End Sub



    Private Sub Button14_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button14.Click

        Dim SecondNumber As Long

        Dim Result As Long

        SecondNumber = TextBox1.Text

        If Operation = "+" Then

            Result = FirstNumber + SecondNumber

        ElseIf Operation = "-" Then

            Result = FirstNumber - SecondNumber

        ElseIf Operation = "*" Then

            Result = FirstNumber * SecondNumber

        ElseIf Operation = "/" Then

            Result = FirstNumber / SecondNumber

        End If

        FirstNumber = Result

        TextBox1.Text = Result



    End Sub



    Private Sub Button16_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button16.Click

        TextBox1.Text = ""

    End Sub



End Class