Ramona,

This works with the active sheet and puts the results in "Sheet 2". It
assumes the invoice numbers are in column A. It's slow, so if you've got
more than a few thousand, go pour a cup of coffee:

Sub test()

Dim last_row As Long
Dim invoice_range As Range
Dim all_invoices() As String
Dim start_num As Long, last_num As Long
Dim i As Long
Dim print_row As Long

last_row = ActiveSheet.Range("A" & Rows.Count).End(xlUp).Row
Set invoice_range = ActiveSheet.Range("A1:A" & last_row)
start_num = ActiveSheet.Range("A2")
last_num = ActiveSheet.Range("A" & last_row).Value
ReDim all_invoices(start_num To last_num)

For i = start_num To last_num
If Application.WorksheetFunction.CountIf(invoice_rang e, i) = 0 Then
all_invoices(i) = "missing"
End If
Next i

Worksheets("Sheet2").Cells.Clear
Worksheets("Sheet2").Range("A1").Value = "Missing Invoices"
print_row = 2

For i = start_num To last_num
If all_invoices(i) = "missing" Then
Worksheets("Sheet2").Range("A" & print_row) = i
print_row = print_row + 1
End If
Next i

End Sub
hth,

Doug Glancy

"Ramona" wrote in message
...
After not wanting to, it looks like I do need to create a
macro. How would I do the following to make sure that it
captures a range of missing numbers (1006-1008 below)? I
need to find all gaps in the Invoice # list and flag the
numbers to a new worksheet(#2), preferably all listed in
Column A without gaps.

Worksheet #1 Worksheet #2
Invoice# Customer Invoice#
1001 Acme 1003
1002 Davis 1006
1004 Shopstar 1007
1005 Walker 1008
1009 Trains

Thanks for any help.