Naughty memorized 180 words last month, which was 1/5 more than planned. How many words did Naughty plan to memorize last month?
淘气上月背了180个单词，比计划多背了(1/5)，淘气上月计划背了多少个单词？
<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>