Xiaogang and his classmates bought 3 pens in total, paid the salesperson 20 yuan, and got back 0.8 yuan. How much is each pen on average?
小刚和同学一共买了3枝钢笔，付给营业员20元，找回0.8元，平均每枝钢笔多少元？
<gadget id="calculator">20 - 0.8</gadget>
<output>19.2</output>

<gadget id="calculator">19.2 / 3</gadget>
<output>6.4</output>

<result>6.4</result>