Last year, a certain landscaping planted 400 more poplars than willows, and 5 times more poplars than willows. How many willows were planted in the greening area?
某绿化去今年种杨树比柳树多400棵，杨树是柳树的5倍，绿化区种柳树多少棵？
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">400 / 4</gadget>
<output>100</output>

<result>100</result>