You're supposed to guess the price of an item, which is between $1 and $1000, and if you're wrong, you're told whether your guess was above or below the price. So the optimum strategy is binary search: start with $500, if it's higher guess $750, and so on... When I watched it today, the guy found out the price was between $700 and $750, so he started guessing 701, 702, 703, 704, so on. The price was $746.