Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub

    Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
        Dim n, m As Double
        n = CDbl(Me.txtFirst.Text)
        m = CDbl(Me.txtSecond.Text)
        Me.output.Items.Clear()
        Me.output.Items.Add(n + m)

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim n, m As Double
        n = CDbl(Me.txtFirst.Text)
        m = CDbl(Me.txtSecond.Text)
        Me.output.Items.Clear()
        Me.output.Items.Add(n - m)
    End Sub

    Private Sub btnMul_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnMul.Click
        Dim n, m As Double
        n = CDbl(Me.txtFirst.Text)
        m = CDbl(Me.txtSecond.Text)
        Me.output.Items.Clear()
        Me.output.Items.Add(n * m)
    End Sub

    Private Sub btnDiv_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDiv.Click
        Dim n, m As Double
        n = CDbl(Me.txtFirst.Text)
        m = CDbl(Me.txtSecond.Text)
        Me.output.Items.Clear()
        Me.output.Items.Add(n / m)
    End Sub
End Class