There are three pen holders, each with 8 pens on average, the first pen holder has 6 pens, the second pen holder has 10 pens, and the third pen holder has how many pens.
有三个笔筒，平均每个笔筒里有8枝笔，第一个笔筒里有6枝笔，第二个笔筒里有10枝笔，第三个笔筒里有多少枝笔．
<gadget id="calculator">8 * 3</gadget>
<output>24</output>

<gadget id="calculator">24 - 6 - 10</gadget>
<output>8</output>

<result>8</result>