I'm tempted to ask what our response will be when we are gambling and our kinds come to ask what we are doing. Do we lie to them or tell them the truth. At a certain age children become so inquisitive that they ask questions virtually in everything they see us do.
Tell half the truth. Daddy is playing. That's it. It's just a game. Don't tell them you are putting money into your game because that will change the definition of it. Kids today do understand how game works and casino games just look like games in their eyes too. If they find it boring they would not even ask the same question again.
But, it's still better if they won't see us doing it. I am playing in the living room but I do try to hide it as always or just keep the kids busy first whether it's watching television or their busy with their smartphones.
Because there's a chance they will bump into the same game you are playing in some advertisements and you won't like explaining things to a kid because their questions are unstoppable and we cannot just shut them up or else they will pursue to find whatever game we are playing.
The other way to prevent them from gambling is to not let them handle money. I give my firstborn money that is just enough in case something really bad happens like he forgot his food or he gets so thirsty in school. But that never happened yet and he is saving all the money I gave in his piggy bank.
Or just keep kids busy with something else, and they wont be so much interesting in sitting with adults and watching them play. There are few ways adults gamble - using gadgets, then you are so much against kids watching, just swipe app or alt+tab the page. If you gamble IRL, lets say around the table, then invite other gamblers that have kids also. Kids will be busy for whole evening and wont even come to table to look what you are doing.