Chaim,
Take a look at the help file for the padl() function Sergey showed you.
>OK
>It's only example.
>If the value in 1 I need 00001
>If the value is 10 I need 00010
>If the value is 100 I need 00100
>If the value is 1000 I need 01000
>If the value is 10000 I need 10000