Card Sharks had a number of different runs. It originally aired on NBC from 1978 to 1981 and then on CBS from 1986 to 1989. It was hosted by Gene Woods and featured two contestants, a new contestant (red name tag) and the returning champ (blue name tag). Contestants would play for money (up to $32k). By the time the show was over, returning champions could continue playing until they reached $75k).
In Card Sharks, each player was assigned a big deck of cards. The player would then be asked to guess the number of times 100 survey respondents responded to demographically specific questions in the same way. The opponent would then be asked whether or not the guessed number was too high or too low. The player with the closest answer would play their cards first. Players had 5 base cards from their deck, the first one of which was shown to the player. The player would then have to guess whether or not the next card in the base set was higher or lower than the previous card. The first one to get through the 5 cards won that round and would earn some $. The winner of the main game would go on to play the Money Cards bonus round where there were more cards, but the high-low next card premise was the same. In later episodes, there was also a bonus round where the player could win a new car or a trip.