Actually, there are a few more things that can cause this:

1. The columnwidth is too narrow to show the number.

Widen the column or change the font size of that cell. Or change the
numberformat to General.

2. You have a date/time in that cell and it's negative

Don't use negative dates. If excel was helping you, it may have
changed the format to a date. Change it back to General (or some
other number format).

If you need to see negative date/times:
Tools|options|Calculation Tab|and check 1904 date system
(but this can cause trouble--watch what happens to your dates
and watch what happens when you copy|paste dates to a different
workbook that doesn't use this setting)

3. You have a lot of text in the cell, the cell is formatted as Text.

Format the cell as general.

4. You really have ###'s in that cell.

Clean up that cell.

5. You have # in a cell, but it's format is set to Fill.

Change the format
(format|cells|alignment tab|horizontal box, change it to General.

Aqib Rizvi wrote:

Nat

### Occurs when a column is not wide enough, or a negative date or
time is used. Check for the text being written in the cell, is it
generating an answer falls in the above two categories.

Aqib Rizvi

--

Dave Peterson