As Maryland’s sports wagering market continues to grow, attention has been turning to the state’s next betting frontier — iGaming, which involves wagering on virtual slot machines and other casino games. The number of mobile sportsbooks in the state jumped to 11 in July and then reached 12 on Thursday, with license approval for Greenmount Station and its operator partner Parx Interactive, according to the Maryland Lottery and Gaming Control Agency, which oversees betting and casinos in the state. There are also 10 retail sportsbooks.