There are 180 pine trees, 30 more than 25% of poplar trees. How many poplar trees are there?
松树有180棵，比杨树的25%还多30棵，杨树有几棵？
<gadget id="calculator">180 - 30</gadget>
<output>150</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">150 / (1/4)</gadget>
<output>600</output>

<result>600</result>