This year's production is reduced (1/5) compared with last year's. What is the production volume of this year's last year?
今年比去年减产(1/5)，今年产量是去年的多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>