Xiaohong bought 8 books with 200 yuan and got back 72 yuan. How much is each book on average?
小红用200元买了8本书，找回72元，平均每本书多少钱？
<gadget id="calculator">200 - 72</gadget>
<output>128</output>

<gadget id="calculator">128 / 8</gadget>
<output>16</output>

<result>16</result>