such as video poker, blackjack, or Caribbean Stud Poker, it is possible to compute an optimal playing strategy based on the average payoff (the amount of payoff times the chance of payoff). Because the jackpot of a progressive game constantly grows, it sometimes exceeds the break-even point for players, such that the jackpot wager becomes a "positive expectation bet" for the player, with an average return to player (RTP) of greater than 100%. When the progressive jackpot is less than the break-even point, there is a negative expected value (house edge) for all players. In the long run, with optimal strategy, a player can profit by only playing progressive games when their jackpots are above the break-even point, although the "long run" can be quite long, tens of thousands of plays. The break-even point cannot be easily calculated on a slot machine game, because the payback percentage for the game is normally unknown to the player. The break-even point in poker-based games can be calculated because the payback percentage for the game is a function of the paybacks and odds of the poker hands, which is based on a standard 52-card deck. The return of a slot machine is based on the published paytable, but also on the normally unpublished reels. For a five-reel slot machine, the player would need to know each symbol on each of the slot machine's five reels in order to calculate the odds. For a three-reel slot, the reels are normally weighted, and this would not be possible. However, in some circumstances the manufacturer may publish the payout of their machines. Many online casinos allow the same game to be played in multiple currencies, in which case the break-even point and average return to player can change depending on the player's currency choice. This is because the jackpot amount may be converted between currencies so that the same amount is paid out to the winner no matter their currency choice, but the wager required to qualify for the jackpot is not. For example, consider a game that pays a $1000 / €900 / £700 jackpot, but requires a fixed $1 / €1 / £1 wager to qualify for the jackpot. In such cases, it is beneficial for the player to play in dollars, as the qualifying wager is a smaller proportion of the jackpot. Thus the break-even point will always be lower and the return