=concatenate A1,/A1 is not a valid syntax for a formula, so I very much
doubt that you have used that and returned (1).
Perhaps you'd like to tell us what you *have* used?
[Copy and paste from the formula bar; don't try to retype into the
newsgroup.]

Valid syntax could be either =CONCATENATE(A1,"/",A1) or =A1&"/"&A1 but if
you have parentheses around the number then you need to be careful as to
whether that is text or a negative number formatting, and then you'd need to
decide what answer you wanted in which situations.
--
David Biddulph

"Mike" wrote in message
...
I want to change my data, in excel, from the form, e.g (100) to (100/100)
for another software to recognize the data. The data is huge and wish I
could
do it automatically .
I have tried the 'Concatenate' formula but it returns the product of the
formula instead of the form I want it. Any help please?

=concatenate A1,/A1 meant to change (100) to (100/100) returns (1)