Editing Card Sharks (section)

==Gameplay==
{{update|section|date=June 2019|reason=Rules for the 2019 version of the show need to be explained in detail}}
Two contestants are assigned separate oversized decks of 52 [[playing card]]s, which the contestants themselves cut before each game (offscreen prior to 2019), and are dealt the first several cards for their row. The champion (or champion-designate if there were two new contestants) played the red cards on top, while the challenger played the blue cards on the bottom. Each contestant's row of cards had a bracket atop it with their name on it, which was used to mark their "base cards". The goal is to complete a row of cards by correctly predicting whether the next is higher or lower in value, similarly to [[Acey Deucey (card game)|Acey Deucey]].

===Main round===
Contestants alternately respond to questions to gain control of the cards. In all versions from 1978 to 1989, the returning champion was usually selected to go first; if there were two new contestants, a backstage coin toss determined the player who sits in the champion's position. The 2019 revival instead has both contestants cut their decks onstage and show the resulting bottom card; the contestant with the higher card goes first.

Similarly to another Goodson-Todman game show, ''[[Family Feud]]'', survey questions are posed to groups of 100 people, all of whom are typically in a common demographic group. (For example, "We asked 100 teachers, 'Has a student ever given you an apple?' How many said they have?"). Contestants are asked to predict how many of those 100 people responded in a specific manner. Their opponent is then asked whether he or she thinks the actual number is higher or lower than the previous contestant's response. The actual number is then revealed, and if the opponent is correct, they play their cards first; otherwise, the contestant to whom the question was posed plays first.

The contestant who wins the question is shown the first card in their row of seven (five from 1978 to 1989 and ten in the first season of the 2019 revival) and can either keep it or replace it with the next card off the top of their individual deck, which he or she is then required to play. The contestant then guesses whether the next card in the row is higher or lower and continues to do so as long as he or she guesses correctly. If the next card is the same rank as the previous, or if the contestant makes an incorrect guess, that contestant loses control, and whatever cards they have played are discarded and replaced. The opposing contestant then has a chance to play from his or her base card, without the opportunity to exchange first. Either contestant can also elect to "freeze" their position if they are unsure of the next card. This prevents the opponent from playing and resets the contestant's base card to the frozen card, and whatever cards that were turned in that instance are not discarded.

If neither contestant has guessed all the cards in his or her row correctly, or if one has frozen his or her position, play continues with another toss-up question, with the opposing contestant providing the initial numerical guess. In all versions from 1978 to 1989, as well as the ''Gameshow Marathon'' episode, the first two games consisted of a maximum of four questions each, and the third tie-breaker game contained a maximum of three questions; since 2019, only one game is played per match, with a maximum of five survey questions. If the contestants still have not cleared their row of cards prior to the last question of the round, that question is played as "sudden death.". The winner of the sudden death question can either play their cards—and change their base card if they desired—or pass to their opponent, who has to play without the option to change the base card. If either contestant guesses incorrectly, their opponent automatically wins the game.

In all versions from 1978 to 1989, as well as the ''Gameshow Marathon'' episode, matches were best two-out-of-three, with the third game being played with three cards per contestant and a maximum of three high-low questions. Each game win was worth $100. The 2019 revival removes the "best two-out-of-three" aspect, with only one game now being played per match; whoever wins the game now receives $10,000 to use as a starting stake in the Money Cards.

====Rule changes====
In the 1980–1981 season, a $500 bonus was awarded to any contestant who provided the exact number of people responding to a specific question, a rule that was modified in the 1986–89 version. In the final few months of 1981, if a contestant was able to complete their row of five cards successfully without freezing or guessing wrong once, he or she won a $500 bonus. These bonuses were guaranteed regardless of the outcome of the overall match, meaning a contestant keeps the cash bonus regardless of winning or losing.

The 1986–89 version added two new varieties of questions in addition to the traditional survey questions. The traditional surveys could also be conducted with a group of ten in the studio audience who shared a characteristic (e.g., ten single women, ten security guards, ten people over 80). Because the odds of being exact were much higher (1:10 compared to 1:100), the exact guess bonus for this type of question was reduced to $100, and the group of ten shared a $100 bonus. The same poll group was used for a week's worth of episodes. The other change was to add general knowledge trivia questions into the game beginning in October 1986. Known as "educated guess questions," the contestant in control gives a numerical answer to the question, similar to a survey, but often much higher numerals that had to be posted as a Chyron on the screen instead of being on the contestant's podium. The opponent, as usual, must guess higher or lower than the answer. Exact guesses won a $500 bonus for the contestant.

The 1986–87 syndicated version introduced prize cards that were shuffled into the deck. If a card was revealed, that contestant was credited with the prize and claimed it if he or she won the game. The next card from the top of the contestant's deck replaced the prize card, and the contestant continued playing. At this time, the maximum number of questions per game was changed to a 4–3–2 format. Shortly thereafter, game #1 was also changed to a three question maximum, moving to a 3–3–2 format. However, all games reverted to the 4–4–3 format by December 1986. Also, contestants only won the prizes claimed for winning the match, or $100 if no prize cards were found during gameplay.

In 1988, the tie-breaker round changed to a single sudden death question. The controlling contestant was shown both base cards before being given the option to play the cards (and change their base card if desired) or pass to the opponent (who had to play without changing). As before, if either contestant guessed incorrectly, their opponent automatically won the match.

The 2019 version added percentage questions in addition to the traditional survey questions; otherwise, gameplay remains the same. There are no cash bonuses offered for an exact guess.

===Money Cards===
The winner of the main game plays the Money Cards bonus game. The original board consisted of a series of eight cards dealt out on three levels; the 2001 revival changed this to seven cards. The champion is staked with a dollar amount before the round begins and wagers money on each card prior to calling higher or lower. A correct call adds the wager to their bank, while a miss deducts it. Prior to 2001, the player was staked with $200 prior to the round.

After calling the first three cards, the last card in the row was moved to the first position in the second row, and the contestant received an additional $200 to wager with the next three cards. The last card in the third row was moved to the first position in the top row, and the contestant made a wager for the final card. The minimum bet for each card was $50 ($100 in the 2001 revival), except for the final card, the "Big Bet" (renamed "Major Wager" for the 2001 revival), where the contestant was required to wager at least half of the money earned thus far.

If a contestant lost all the money banked ("busted") on the first row, the last card called was moved to the first position on the second row and the contestant received another $200 to wager with the final four cards. If the contestant busted after moving up to this level on either the original or 1986 series, the game ended.

If a contestant wagered their entire bank on each card and made a correct prediction each time, the maximum payout was stated to be $28,800 on the original 1970s series, $32,000 on both 1980s series, $51,800 on the 2001 series, and $640,000 on the 2019 series. As of 2021, the only contestant that has successfully achieved this feat is Norma Brown, who won $28,800 in 1978.

On the NBC version, a champion was allowed a maximum of seven wins. On the CBS series, champions were retired either by reaching five wins or surpassing the network’s winnings limit.

Starting in 2019, the player's winnings are represented in oversized $500, $1,000, $5,000, $10,000, and $25,000 chips. The board is now a single row of seven cards, with no additional money given halfway through. Players are given the chance to change any one card during the round. Players are required to physically place chips equal to their bet on a table in front of them on sections labeled "HIGHER" or "LOWER". Prior to the last card, players must bet at least $1,000 on each card. Players who reach the last card without busting are given the option to "cash out" and quit with their current winnings rather than play the final card. If they elect to play, they must gamble at least half their bank on the last card. The maximum possible payout is $640,000.

====Rule changes====
Duplicate cards were originally counted as incorrect guesses, in the same manner as in the main game. Starting on October 20, 1980, a duplicate in the Money Cards rounds was regarded as a "push"; the contestant did not lose their wager, and moved to the next card. The "push" rule remained intact until late in the 2001 revival's run. In the first season of the 2019 revival, a duplicate card was treated as an incorrect guess; in the second season, it was again treated as a push.

Initially, contestants could only change their base card on the bottom level of the board, at the start of the round. This was later altered to allow the contestant to change the base card on each new line of cards if they so desired.

During the 1986–89 version, three extra cards (known as "spare cards") were positioned to the left of the Money Cards board. These cards could be used initially any time to change an undesired card, even to change the same card multiple times, but during the run were later amended to allow only one change per line at any point in the line. The additional amount awarded for moving to the second line increased from $200 to $400. This changed the maximum potential payout to $32,000.

On the 2001 series, each winning contestant's score from the main game was divided by three; therefore, players started the round with $700 to wager with and that amount was added to their score once they reached both the second level ''and'' the Major Wager, which was a ''Card Sharks'' first.

Players can change exactly one card, anywhere on the line, in the 2019 version.

===Car games===
Beginning in the fall of 1986, champions were also given an opportunity to win a new car following the Money Cards round. The car round made its debut on the syndicated series shortly after its debut, with the daytime series adopting the round in October 1986.

Three [[Joker (playing card)|jokers]] were shuffled into the Money Cards deck. If a joker was uncovered, it was replaced with the next card from the top of the deck, and the contestant was given an additional chance to win a car. To ensure the contestant had one opportunity at winning the car, they were given one free joker at the onset of the Money Cards.

Following the Money Cards, a row of seven new cards were shown to the contestant, behind one of which was the word "Car". Using the joker(s) from the Money Cards, the contestant designated the cards of their choice. If one of the cards selected revealed the word "Car", the contestant won a new vehicle in addition to any money and prizes won earlier. The same car was featured for an entire week of five shows. During the special weeks when children played, the top prize was a trip to [[Hawaii]] and the children were given two jokers to start.

In July 1988, the bonus changed to feature an audience poll question similar to those used in the main game. The contestant was read the question and registered their guess on a board with a range from zero to ten. If the contestant made a correct prediction, they won the car. If their guess was off by one, the contestant won another $500.

The daytime series had no limit on how many cars a champion could win, but the syndicated series did. Initially, winning a car meant the champion retired, but after several weeks the show began allowing champions to continue playing after winning a car. A limit was then placed on how many cars could win before retiring, with the limit eventually being set at two. The changes coincided with a changing in cars being offered; the round started out by offering high-end General Motors cars such as Cadillacs and Corvettes, later changing to mid-priced offerings like Chevrolet Camaros and Pontiac Fire Birds, and then finally to various offerings from American Motors through its Renault and Jeep brands.