See if this gets you started
Sub addTeamScores(oshp As Shape)
Dim score As Long, TeamAScore As Long, TeamBScore As Long
Dim osld As Slide
Set osld = ActivePresentation.SlideShowWindow.View.Slide
'there will be an error if box is not a number
If Not IsNumeric(osld.Shapes("ScoreBoard").TextFrame.TextRange) Then _
osld.Shapes("ScoreBoard").TextFrame.TextRange.Text = "0"
If Not IsNumeric(osld.Shapes("Score1").TextFrame.TextRange) Then _
osld.Shapes("Score1").TextFrame.TextRange.Text = "0"
If Not IsNumeric(osld.Shapes("Score2").TextFrame.TextRange) Then _
osld.Shapes("Score2").TextFrame.TextRange.Text = "0"
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
score = CLng(osld.Shapes("ScoreBoard").TextFrame.TextRange.Text)
TeamAScore = CLng(osld.Shapes("Score1").TextFrame.TextRange)
TeamBScore = CLng(osld.Shapes("Score2").TextFrame.TextRange)
Select Case oshp.Name
Case "Add1"
osld.Shapes("Score1").TextFrame.TextRange.Text = CStr(TeamAScore + score)
Case "Add2"
osld.Shapes("Score2").TextFrame.TextRange.Text = CStr(TeamBScore + score)
End Select
End Sub