public Class Form1
    Inherits System.Windows.Forms.Form
 
    Dim a As Integer
    Dim b As Integer
    Dim c As Double
 
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
  System.EventArgs) Handles Button1.Click
        End
    End Sub
 
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button2.Click
        a = System.Convert.ToInt32(TextBox1.Text)
        b = System.Convert.ToInt32(TextBox2.Text)
        c = a + b
        TextBox3.Text = c
    End Sub
 
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button3.Click
        c = a - b
        TextBox3.Text = c
    End Sub
 
    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button4.Click
        c = a * b
        TextBox3.Text = c
    End Sub
 
    Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button5.Click
        c = System.Convert.ToDouble(a / b)
        TextBox3.Text = System.Math.Round(c, 3)
    End Sub
 
    Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button6.Click
        TextBox1.Clear()
        TextBox2.Clear()
        TextBox3.Clear()
    End Sub
End Class