The current price of a sweater is 100 yuan, which is 20% lower than the original price. How much is the original price?
一件毛衣现价100元，比原价降低了20%，原价多少钱？
<gadget id="calculator">20 / 100</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">100 / (4/5)</gadget>
<output>125</output>

<result>125</result>