Each pen is 15 yuan, and each stationery box is 9 yuan. The money to buy 6 pens is exactly how many pencil cases can be bought.
钢笔每支15元，文具盒每个9元，买6支钢笔的钱正好可买文具盒多少个．
<gadget id="calculator">6 / 9</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">15 * (2/3)</gadget>
<output>10</output>

<result>10</result>