First, copy and paste your data to create your new column. Then, in any
blank cell, enter -1. Copy this cell. Then select your new column of data
and Paste Special. Select "Multiply" in the Paste Special dialog box. Click
OK. Your data should now be converted from positive to negative (or vice
versa). You can then delete the -1 you entered earlier.

HTH,
Elkar

"JRoseen" wrote:

Excel 2003. We would like to copy a column of numbers and then convert the
whole column (each number in the column) from positive to negative. Can this
be done?