Simple Hack Mechanism

I would like to know if there's an easy way on automating an attack to a certain page which only has 2 page elements:

-1 numeric field with 5 digit limitation
-a submit button

Basically, if the user pressed the submit button, the system validates the digits entered and if it matches the system requirements, it will let the user go to the next page.

Does this kind of hack thing exist? Thanks a lot!