The school bought 800 exercise books, kept 80 for spare, and distributed the rest to 12 classes. How many exercise books are allocated to each class on average.
学校买来800本练习本，留下80本备用，其余的分给12个班．平均每个班分得多少本练习本．
<gadget id="calculator">800 - 80</gadget>
<output>720</output>

<gadget id="calculator">720 / 12</gadget>
<output>60</output>

<result>60</result>