The school bought 18 packs of exercise books, each with 60 books. If each class is divided into 90 books, how many classes can these exercise books be divided into?
学校买来18包练习本，每包60本，如果每班分90本，这些练习本能够分给几个班？
<gadget id="calculator">60 / 90</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">18 * (2/3)</gadget>
<output>12</output>

<result>12</result>