In this year's Arbor Day, the fifth graders of Dongfang Primary School planted 180 trees (1/5) more than the third graders. How many trees were planted by the third graders of Dongfang Primary School?
在今年的植树节活动中，东方小学五年级同学植树180棵比三年级多植(1/5)，东方小学三年级学生植树多少棵？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">180 / (6/5)</gadget>
<output>150</output>

<result>150</result>