Adding two cells then dividing by another

I'm trying to create a sheet that will maintain a running average of my score when I'm playing darts.

B2 = Where I input my score
B3 = Displays my average
B4 = +1 just gets added here everytime I click the button.

The part where I try to define B3 as being B2 + B3 / B4 is the problem.

Private Sub CommandButton1_Click()
    Range("B4").Value = Range("B4").Value + 1
    Range("B3").Value = Range("B2").Value + Range("B3").Value / Range("B4")
    Range("B2").Select
    Selection.ClearContents
    Range("B2").Select
End Sub