If the current price of a commodity is 20 yuan lower than the original price (1/5), what is the original price of the commodity?
一种商品现价比原价降低了(1/5)后是20元，那么商品的原价是多少元．
<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>

<gadget id="calculator">20 / (4/5)</gadget>
<output>25</output>

<result>25</result>