I did initially misunderstand this question and had to be helped along, but it is fairly difficult to do on the fly anyway: "We're playing a game with an unbiased 30-sided die. Before we roll, we both pick (distinct) numbers between 1 and 30, and then we roll the die. If the number that appears is closer to the number I picked, you pay me, in dollars, the number on the die; if it is closer to the number you picked, I pay you, in dollars, the number on the die; if it is equidistant we do nothing. What's the optimal strategy - do you go first or second, and how do you pick your number? What's your expectation?"
