Clockwise from left, Prince Antwi, Monica Harmon, Munachiso Iherobiem and Marquis Douglas of Orange, New Jersey, compete in the Youth North American Bridge Championships. (Francesca Canali/American Contract Bridge League)

When Reginald Smith heard about a bridge club at his school, he thought he and his friends “would be building” — making model bridges or learning about construction.

“But then I found out that it was cards,” he said late last month, standing outside a bustling ballroom at the Marriott Wardman Park hotel in Washington. More than 200 young bridge players were swirling around him, finishing lunch and preparing for their next match.

“And,” he said, “I found out that it was something I could dominate at because I’m good at math,” which helps with keeping track of what cards have and have not been played.

Reginald, 14, has been playing bridge for the past four years as part of a club at Oakwood Avenue Community School in Orange, New Jersey. He and about a dozen club members drove from Orange to compete in the ninth annual Youth North American Bridge Championships, a ­weekend-long tournament that started July 28.

Many people think that bridge is just a complicated card game played by senior citizens in retirement homes. It’s true that bridge isn’t as popular as it was in the mid-20th century. But more and more kids are playing it and enjoying it. This year’s Youth NABC, put on by the American Contract Bridge League, was the organization’s largest tournament for kids. Forty players even came from China to compete.

A bridge game in process at the 2016 Youth North American Bridge Championships in Washington. (Francesca Canali/American Contract Bridge League)

Bridge is a four-person game played with teams of two. To win, your team needs to win tricks: sets of four cards, one from each player. Players bid on how many tricks they think they can win and are dealt 13 cards. The first card that is played in the trick determines the lead suit (spades, hearts, diamonds or clubs). Then, going around the table, whoever plays the highest card in that lead suit wins the trick.

Things get complex during the bidding process, when players can also determine a trump suit. Cards in a trump suit can win any trick, making them particularly valuable.

“The hardest part about the game, for me, is bidding,” said Snehal Oberai, 12, whose mother taught her to play bridge about four years ago. “You have to know a lot of things: how to deal with the cards in your hand and how to communicate with your partner,” without saying such things as “I have some really great cards,” so they know the strength of your hand.

Snehal is a rising eighth-grader at Rocky Run Middle School in Chantilly, Virginia, where she started a bridge club to encourage other students to play the game. There aren’t a ton of kids who know how to play bridge, she says, which makes tournaments a fun way “to meet new people and maybe even play with some friends.”

She even cut short a vacation in India, she said, “just to be here.”