Card counting is the process whereby players keep a ‘running count’ of the number of high and low cards in the deck. Values of 1 and -1 are assigned to specific ranges of cards. If there is a negative count, it means that more high cards have been dealt and few remain in the deck. This is advantageous to the dealer. If the count is positive, this means more low-value cards have been dealt and more 10-value cards remain in the deck. This is advantageous to the player. Card counting is ineffective when multiple decks are used, and when continuous shuffling is employed.