The verb giocare means "to play," in the sense of playing a game or a sport. When referring to sports, it is usually followed by the Italian preposition a:

I bambini giocano sull spiaggia. (The children play on the beach.)

Mario e Carlo giocano a carte. (Mario and Carlo play cards.)

Paola gioca molto bene a tennis. (Paola plays tennis very well.)

The phrase giocare dazzardo means "to gamble":

Pietro gioca dazzardo e perde sempre. (Pietro gambles and always loses.)