In Blackjack, the value of a hand is determined by adding up the point values of the individual cards. Number cards from 2 to 10 are worth their face value, while face cards (kings, queens, and jacks) are each worth 10 points. Aces can be worth either 1 or 11 points, depending on which value benefits the hand more without exceeding 21. The total value of the hand is the sum of these card values, and players aim to get as close to 21 as possible without going over. If the total exceeds 21, the hand is considered "bust," resulting in a loss.