Xiaogang, Xiaoming, and Xiaohong bought pencils. Xiaogang said, I bought 7 pencils. Xiaoming said, if I give Xiaohong 3, the three of us will be the same. Do you know how much they bought in total? a pencil?
小刚，小明，小红三人买铅笔，小刚说，我买了7只铅笔，小明说，我给小红3只的话，我们三人就一样了，你知道他们三人一共买了多少支铅笔吗？
<gadget id="calculator">7 * 3</gadget>
<output>21</output>

<result>21</result>