I'm making a basic calculator, so far I have programmed the addition, subtraction, multiplication and division without any problems. I want to add a memory, memory recall and memory clear button but I'm not sure how to go about them.

Here is the code I have for the other buttons so far.

Code:
Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim num1, num2, ans
        Try
            num1 = Val(TextBox1.Text)
            num2 = Val(TextBox2.Text)
            ans = num1 + num2
            MessageBox.Show(ans)
        Catch ex As Exception
            MessageBox.Show(Err.Description)
        End Try
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Dim num1, num2, ans
        Try
            num1 = Val(TextBox1.Text)
            num2 = Val(TextBox2.Text)
            ans = num1 - num2
            MessageBox.Show(ans)
        Catch ex As Exception
            MessageBox.Show(Err.Description)
        End Try
    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Dim num1, num2, ans
        Try
            num1 = Val(TextBox1.Text)
            num2 = Val(TextBox2.Text)
            ans = num1 * num2
            MessageBox.Show(ans)
        Catch ex As Exception
            MessageBox.Show(Err.Description)
        End Try
    End Sub

    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        Dim num1, num2, ans
        Try
            num1 = Val(TextBox1.Text)
            num2 = Val(TextBox2.Text)
            ans = num1 / num2
            MessageBox.Show(ans)
        Catch ex As Exception
            MessageBox.Show(Err.Description)
        End Try
    End Sub
End Class
Could somebody give me the code for the memory buttons?

(Thanks)