Format an empty cell the same as in the range you want to multiply,
put 1000 in the same cell, copy it, select the numbers and do
edit>paste special and select multiply
In a blank cell somewhere (away from where your numbers are) enter the
number 1000. Select the cell again and click <copy>, then highlight
all the numbers you wish to change and click on Edit | Paste Special |
Values (check) | Multiply (check) | OK then <Esc>.
You can then delete the 1000 from the original cell.