Mr. Wang spent 87.8 yuan on science books and story books, 39.2 yuan on science books, and 6 story books. How much is each?
王老师买科技书和故事书共用了87.8元，科技书花了39.2元，故事书有6本，每本多少元？
<gadget id="calculator">87.8 - 39.2</gadget>
<output>48.6</output>

<gadget id="calculator">48.6 / 6</gadget>
<output>8.1</output>

<result>8.1</result>