Excel Custom Number Formatting

[jbissaillon]

I am attempting to create a spreadsheet for the small office I work for
that contains workstation numbers, serial numbers, product id's, etc.
I am having trouble with the custom number format I have created for
Microsoft Office Product Id numbers.

Example:

I want to input: 12345678912345678912
. . . and see: 12345-678-9123456-78912

this is the number format I created: #####-###-#######-#####
.. . . and this is what I get: 12345-678-9123456-00000

I canot get the last five numbers to show anything but zero's.

Any suggestions?

I am using Office 10.1.6 for mac, and I will be updating the entire
office to Office 2004 for mac later this week.

Thanks.