yes gambling is ok as long as long as your doing it in a right and apropriate way.  gambling is not a sin at all because gambling itself is an act of playing and betting a certain amount of cash or any other things that has a specified value for a chance to double it but of course theres no guarantee or assurance that you can double it due to the fact that gambling is a verry risky game to play. a sin is act of doing inapropriate things like killing a human or an animal that is inocent and not intended to be killed.