Uncle Li harvested 90 tons of wheat this year, 20% more than last year. How many tons of wheat did he harvest last year?
李伯伯今年收小麦90吨，比去年增产二成，他去年收小麦多少吨？
<gadget id="calculator">20 / 100</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">90 / (6/5)</gadget>
<output>75</output>

<result>75</result>