The Chinese teacher has to correct 48 test papers in the class, and has already corrected 12. If 9 test papers can be corrected every hour, how many hours will it take?
语文老师要批改全班48份试卷，已经批改了12份，如果每小时可以改9份，还要几小时才能改完？
<gadget id="calculator">48 - 12</gadget>
<output>36</output>

<gadget id="calculator">36 / 9</gadget>
<output>4</output>

<result>4</result>