I have experienced this problem before, and I believe it to be a bug in the older version of FileMaker. It is not just with 10s and 1s, but also with 20s and 2s, 30s and 3s, and so on. When creating the database it was tested in FM 10 and this was not an issue, however the production environment for my client was FM 8.5 and that is when we noticed this bug. My suggestion would be to upgrade to FM 10 to avoid this issue.
If you have to use FM 8.5, then a workaround might be to add a space after the 1 in the value list so it looks like "1 ". Then use a calculation field to trim out the extra spaces so you can show the actual number.
Hope this helps
Thanks for this information u can save my time and effort.