Common card counting systems in Blackjack are designed to give players an advantage by tracking the relative proportion of high to low cards remaining in the deck. These systems vary in complexity but generally involve assigning values to different cards, which helps players assess when the odds favor them. The more popular systems, like the Hi-Lo method, simplify this process by using a systematic approach to counting, allowing players to adjust their betting strategies accordingly. Effective use of these systems requires practice and a strong understanding of the game, ultimately enabling players to make more informed decisions and increase their chances of winning.