Method of operating progressive reel slot machines and device therefor

A slide rule calculator for determining the current expected progressive return of various progressive reel slot machines, each having a current dollar amount of the progressive jackpot, a probability of hitting the progressive jackpot, and a truncated return, the slide calculator comprising:

• (a) a card member having a first column of symbols representing various values of probabilities of hitting the progressive jackpot for various progressive reel slot machines, which probabilities increase as an exponential function of a base number, and having an array of symbols representing various values of the current expected progressive return of the various progressive reel slot machines, said array having at least one array column and having rows aligned with said symbols of said first column;
• (b) a middle sleeve slidable over said card member, having a first window located over said first column of symbols, and having a second window located over said array;
• (c) said middle sleeve having a second column of symbols representing various dollar amounts of the current progressive jackpot, which dollar amounts increase as an exponential function of said base number;
• (d) an outer sleeve slidable over said middle sleeve, and having a third window located to expose said first window in said middle sleeve and any symbol of said first column of symbols visible therethrough;
• (e) said outer sleeve having a fourth window located to expose at least one of said symbols of said second column on said middle sleeve and an aligned row of said array on said card member;
• and
• (f) said outer sleeve having indicia associated with array columns visible through said fourth window.

A slide rule calculator for determining the current expected progressive return of various progressive reel slot machines, each having a current dollar amount of the progressive jackpot, a probability of hitting the progressive jackpot, and a truncated return, the slide calculator comprising:

• (a) a card member, a middle sleeve and an outer sleeve;
• (b) the card member having a first column of symbols representing various values of probabilities of hitting the progressive jackpot for the various progressive reel slot machines, which probabilities increase as an exponential function of a base number, and having an array of symbols representing various values of the current expected progressive return of the various progressive slot machines, said array having at least one array column and having rows aligned with said symbols of said first column;
• (c) said middle sleeve being slidable over said card member and having a first window located over said first column of symbols, said first window being sized and shaped to expose one of said symbols of said first column;
• (d) said middle sleeve having a second column of symbols representing various dollar amounts of the current progressive jackpot, which dollar amounts increase as an exponential function of said base number, said symbols of said second column being spaced apart a distance equal to a distance between said rows of said array such that said symbols of said second column are alignable with said rows of said array;
• (e) said middle sleeve having a second window located over said array, said second window extending at least from a top of said second column of symbols to a bottom thereof and having a width sufficient to expose all of said array columns;
• (f) said outer sleeve being slidable over said middle sleeve, having a longitudinal axis and a lateral axis, and having an elongated, longitudinally-extending window located to expose said first window in said middle sleeve and any symbol of said first column of symbols visible therethrough, said longitudinally-extending window having a length substantially equal to a distance from said top of said second column to said bottom thereof;
• (g) said outer sleeve having a laterally-extending window located to expose one of said symbols of said second column on said middle sleeve and an aligned row of said array on said card member;
• (h) said outer sleeve having indicia associated with array columns visible through said laterally-extending window, said indicia representing various values of truncated return of progressive slot machines;
• and
• (i) the values of the current expected progressive return represented by said array of symbols being determined by an exponential function of said base number plus a number representing truncated return of progressive slot machines, each column of said array representing a different value of truncated return;
• (j) whereby the current expected progressive return of a certain progressive slot machine at a particular point in time can be obtained with the slide calculator by sliding the card member relative to said middle sleeve such that a symbol from said first column representing the probability of hitting the progressive jackpot of the certain progressive slot machine is visible through said first window, and then sliding said outer sleeve relative to said middle sleeve and said card member such that a symbol from said second column representing the current dollar amount of the progressive jackpot of the certain progressive slot machine is visible through said laterally-extending window, and then reading the value of the present expected progressive return for the progressive slot machine, which value is associated with said indicia representing the truncated return of the certain progressive slot machine.