The school bought a batch of books. If each class has 20 books, it can be distributed to 9 classes. Now it needs to be distributed to 10 classes. How many books can each class get?
学校买来一批图书，如果每班分20本，可以分给9个班，现在需要分给10个班，每班只能分到多少本？
<gadget id="calculator">9 / 10</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">20 * (9/10)</gadget>
<output>18</output>

<result>18</result>