Teacher Li took 500 yuan to buy books. I bought 12 copies of the same "Encyclopedia", leaving 80 yuan. How much is "Each Encyclopedia"?
李老师带500元去买书．买了12本同一种《百科全书》，剩下80元．《每本百科全书》多少钱？
<gadget id="calculator">500 - 80</gadget>
<output>420</output>

<gadget id="calculator">420 / 12</gadget>
<output>35</output>

<result>35</result>