Teacher Liu took 700 yuan to buy footballs, bought 16 footballs, and left 60 yuan. How much is an average football?
刘老师带700元去买足球，买了16个足球，还剩60元．平均每个足球多少元？
<gadget id="calculator">700 - 60</gadget>
<output>640</output>

<gadget id="calculator">640 / 16</gadget>
<output>40</output>

<result>40</result>