Hi Maxx,
I think the simple way is to use a Pivottable to summarize and sort in
descending order.

If you are not familiar with Pivot table, please refer to below:
http://www.microsoft.com/dynamics/us...s_collins.mspx

Or if you like to learn from video, refer to below:
http://video.google.com/videosearch?...um=4&ct=title#

Hope the above help you.

"Maxx" wrote:

In this case I have input the daily sales manually.

"Nelson" wrote in message
...
Hi Maxx,
I have a couple of questions:
1) Did your inventory information store some where in the Excel?
2) How do you input your sale information? key in manually or a barcode
scanner?
3) Are you using a POS system (Point of sale)? if yes, then you should
work
on the POS software.

"Maxx" wrote:

In a bookshop, I'm monitoring the daily sales of a best selling title The
bookshop is open 7 days a week. Some days are quieter than others (for no
discernable reason).

I need to know how many copies a best selling title to reorder. If sales
are
increasing I will need to replace all that I've sold and order a larger
quantity than I ordered last time, if they are roughly static I'll order
the
same quantity I ordered last time. If they are declining I will order
fewer
than I ordered last time.

Can Excel help here?