Xiaohong, Xiaoming, and Xiaogang bought 12 pencils in total. After they distributed them equally, Xiaohong took out the money for 7 pencils, Xiaoming took out the money for 5 pencils, and Xiaogang didn’t bring any money. Xiaogang wants to take out 2.4 yuan. Smart classmate, do you know how much Xiaohong should get back?
小红、小明、小刚三人一共买了12支铅笔，三人平均分配后，小红拿出7支铅笔的钱，小明拿出5支铅笔的钱，小刚没带钱，后来一算小刚要拿出2.4元，聪明的同学，你知道小红应收回多少钱吗？
<gadget id="calculator">12 / 3</gadget>
<output>4</output>

<gadget id="calculator">2.4 / 4</gadget>
<output>0.6</output>

<gadget id="calculator">7 - 4</gadget>
<output>3</output>

<gadget id="calculator">0.6 * 3</gadget>
<output>1.8</output>

<result>1.8</result>