Question: On my last two trips to Las Vegas I have found slots ($1 machines at the Stratosphere) advertising a return of 98%. I didn’t seem to get a decent return on them. Shouldn’t the casino, in such a regulated business like gambling, at least pay back the percentage they advertise? Dottie C. Answer: When a casino advertises that its slot machines return 98 percent, it means the machine is pre-programmed “over the long run” to return 98¢ of every dollar played. Don’t come to expect that for each dollar inserted you will automatically get 98¢ dribbling back into the tray. The operative phrase here is “over the long run.” A “long run” could mean weeks, months, and even years on any given machine. But let’s assume the machine you were playing was paying off 98¢ for each and every dollar bet. Using a liberal definition of the word “good” machine, we’ll allow the casino a measly 2% edge. Well, Dottie, if you were to insert $60 per minute into a 98% payback slot machine (not difficult on a dollar machine at $3 a whack using a credit button), you will lose about $72 an hour. Multiply that by eight hours of play and you will come up $576 short in the purse. Even on those advertised high payback machines, the casino still has a way of grinding away at your gambling capital. The way you avoid this $576 grind is to behave more conservatively by playing on smaller denomination machines (25¢), for shorter increments of time. Casino operators know all to well that such cautious behaviour has negative implications on the casino win for the house. They would much prefer you ante-up silver slugs and play all day. Oh, by the way, Dottie, all too often players like you believe that the casino is in the gambling business. Wrong! They are in the math business. On pre-programmed slot machines that give the house a certain percentage return, you are the only one doing the gambling here.