Or if you really wanted to play around with ranges, but much less readable/understandable than above
Code:
Sub UpdateMyTips()
Dim myNewTip As Long
Dim myOldTotal As Long
With ActiveDocument.Paragraphs(2).Range.Words(1)
With .Previous(unit:=wdParagraph).Words(1)
myNewTip = CLng(.Text)
.Text = " " & vbCrLf
End With
myOldTotal = CLng(.Words(1).Text)
.Words(1).Text = CStr(myNewTip + myOldTotal) & " "
.Paragraphs(1).Range.InsertAfter Text:=myNewTip & " " & Format(Now(), "DDDD, MMMM d, yyyy") & vbCrLf
End With
End Sub