A pair of trousers is sold at a 20% discount. The current price is 100 yuan. What is the original price of the trousers?
一条裤子八折出售，现在的价格是100元，这条裤子原价是多少元．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">100 / (4/5)</gadget>
<output>125</output>

<result>125</result>