There are 7 poplars in the school, and the number of willows is twice as many as the poplars. How many poplars and willows are there in the school?
学校里有杨树7棵，柳树的棵树是杨树的2倍，求学校里有杨树柳树一共多少棵？
<gadget id="calculator">7 * 2</gadget>
<output>14</output>

<gadget id="calculator">14 + 7</gadget>
<output>21</output>

<result>21</result>