I was recently given a personal check that had only the routing number on the bottom but no account number. There appears to be a number in the top left corner that could be it. Can i cash this check?
Your bank is the entity who could determine if the check is real or not. Bear in mind that it is check kiting (a form of check fraud) to knowing cash a perfectly legitimate check from a bank if the check writer doesn't have sufficient funds to cover the check amount.