Profit from a card game

My son, who is eleven years old, played games of picture cards with friends for keeps and won hundreds of cards. Their overall value is several tens of shekels. Now he’s asking whether he has to give back the cards that he won. Is it considered a big profit that must be returned, or a small profit that he may keep?

If the win was relatively small, you don’t have to give it back, since the loser was ready to tolerate this level of loss. But if the win is big, you do have to give it back, because the loser did not agree, even implicitly, to sustain such losses when he agreed to play.

In your case it depends. If he won the whole sum from just one boy, that is certainly considered a big win, and he has to give it back. But if he made these profits by playing with many different boys, then this is considered a small profit.