>How can I insert hyphens from right to left,
>one after the fourth digit and other after the eighth digit,
>so that the number: 1133412927 becomes 11-3341-2927
>
>Sometimes it can be: 01133412927, and must become: 011-3341-2927
>
>Thanks
>
Moises,

Since the hyphens are not part of the data but just formating the display I would suggest that you leave them out of the data and use TRANSFORM() or the InputMask and Format properties of the controls to display the hypehns where you want them.

? TRANSFORM( "1133412927", "@R 99-9999-9999")
? TRANSFORM( "01133412927", "@R 999-9999-9999")