The unit price of a notebook is 5 times that of an exercise book. How many exercise books can you buy for the price of 4 notebooks?
笔记本的单价是练习本的5倍．买4本笔记本的钱可以买多少本练习本．
<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<result>20</result>