The price of a pen is 24.8 yuan, which is 0.8 yuan more than twice that of a pencil case. How much is the price of a pencil case?
一支钢笔的价格为24.8元，比一个文具盒的2倍还多0.8元，一个文具盒的价格是多少元？
<gadget id="calculator">24.8 - 0.8</gadget>
<output>24</output>

<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<result>12</result>