There are 9 girls in the art group, and the number of boys is twice that of girls. How many students are there in the art group?
美术小组有9名女生，男生的人数是女生的2倍，美术小组共有多少名学生．
<gadget id="calculator">9 * 2</gadget>
<output>18</output>

<gadget id="calculator">18 + 9</gadget>
<output>27</output>

<result>27</result>