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

        'For 문'
        TextBox1.Text = ""
        Label1.Text = "For 문으로 구구단을 3열로 출력합니다."
        For i = 9 To 1 Step -3
            For j = 1 To 9
                For k = 0 To 2
                    TextBox1.Text += ((i + k) & " X " & j & " = " & ((i + k) * j) & "    ")
                Next
                TextBox1.Text += vbCrLf
            Next
            TextBox1.Text += vbCrLf
        Next
    End Sub