Public Class Form1

    Dim total1 As Integer
    Dim total2 As Integer

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles btnOne.Click

        TextBox1.Text = TextBox1.Text & btnOne.Text

    End Sub

    Private Sub Button5_Click(sender As Object, e As EventArgs) Handles btnFive.Click

        TextBox1.Text = TextBox1.Text & btnFive.Text

    End Sub

    Private Sub Button7_Click(sender As Object, e As EventArgs) Handles btnSeven.Click

        TextBox1.Text = TextBox1.Text & btnSeven.Text

    End Sub

    Private Sub Button8_Click(sender As Object, e As EventArgs) Handles btnEight.Click

        TextBox1.Text = TextBox1.Text & btnEight.Text

    End Sub

    Private Sub btnTwo_Click(sender As Object, e As EventArgs) Handles btnTwo.Click

        TextBox1.Text = TextBox1.Text & btnTwo.Text

    End Sub

    Private Sub btnThree_Click(sender As Object, e As EventArgs) Handles btnThree.Click

        TextBox1.Text = TextBox1.Text & btnThree.Text

    End Sub

    Private Sub btnFour_Click(sender As Object, e As EventArgs) Handles btnFour.Click

        TextBox1.Text = TextBox1.Text & btnFour.Text

    End Sub

    Private Sub btnSix_Click(sender As Object, e As EventArgs) Handles btnSix.Click

        TextBox1.Text = TextBox1.Text & btnSix.Text

    End Sub

    Private Sub btnNine_Click(sender As Object, e As EventArgs) Handles btnNine.Click

        TextBox1.Text = TextBox1.Text & btnNine.Text

    End Sub

    Private Sub btnZero_Click(sender As Object, e As EventArgs) Handles btnZero.Click

        TextBox1.Text = TextBox1.Text & btnZero.Text

    End Sub

    Private Sub btnPlus_Click(sender As Object, e As EventArgs) Handles btnPlus.Click

        total1 = total1 + Val(TextBox1.Text)

        TextBox1.Clear()

    End Sub

    Private Sub btnEquals_Click(sender As Object, e As EventArgs) Handles btnEquals.Click

        total2 = total1 + TextBox1.Text

        TextBox1.Text = total2

        TextBox1.Clear()

    End Sub
End Class