You can buy 6 pens with the price of 2 pencil cases, 10 identical books with the price of 3 pens, and how many pencil cases can you buy with the price of 30 books.
买2个文具盒的钱可以买6支钢笔，买3支钢笔的钱可买10本一样的书，买30本书的钱可以买多少个文具盒．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">10 * 1</gadget>
<output>10</output>

<gadget id="calculator">30 / 10</gadget>
<output>3</output>

<result>3</result>