Create a procedure named Auto_Open.

Sub Auto_Open()
With ThisWorkbook.Worksheets("Sheet1").Range("A1")
.Value = .Value + 1 ' note leading periods
End With
End Sub

--
Cordially,
Chip Pearson
Microsoft MVP - Excel
Pearson Software Consulting
www.cpearson.com
(email on the web site)

"Susan" wrote in message
...
I would like to automatically add one number to an existing number each
time
I open that document. (i.e. 5329 to 5330) in the same cell.