There are 20 poplar trees in the campus, and they are (2/3) willow trees. How many willow trees are there?
校园里有杨树20棵，是柳树的(2/3)，柳树有多少棵？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">20 / (2/3)</gadget>
<output>30</output>

<result>30</result>