As long as they're really numbers, you could use a custom format:

Select the column:
format|Cells|number tab|Custom category
0000 00

The value that you see in the formula bar will still be the number--only the
display has changed.

wrote:

I have a file with a column that contains numbers that have six digits. I
need to add a space between the last two digits in this very long column of
numbers. Is there an efficient way of doing this? Example: 120100 needs to
be 1201 00

--

Dave Peterson