Xiao Shao took 500 yuan to buy "Mathematics Little Smart", bought 25 sets, and left 50 yuan. How much does each set cost?
小邵带500元去买《数学小灵通》，买了25套，还剩50元．每套价钱多少？
<gadget id="calculator">500 - 50</gadget>
<output>450</output>

<gadget id="calculator">450 / 25</gadget>
<output>18</output>

<result>18</result>