Okay kiddo, have you ever played a card game before? If so, then you might have seen a card in the deck called a "jack". A jack is a special card that has a picture of a man on it with a fancy hat and a sword.
Now, sometimes in cards games like poker, blackjack, and crazy eights, the jack card is worth more than the other cards. This means that if you have a jack in your hand, you can use it to win a round or beat the other players.
But don't worry if you don't have a jack in your hand! Sometimes they can be a little tricky to figure out, even for adults. But that's what makes playing cards so much fun - you never know what kind of special cards you might get!