There are 200 poplar trees, pine trees are less than poplar trees (1/4), how many pine trees are there?
杨树有200棵，松树比杨树少(1/4)，松树有多少棵．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">200 * (3/4)</gadget>
<output>150</output>

<result>150</result>