A road has been built for 120 meters, and 20% of this road is left. How long is this road in meters?
一条路已经修了120米，还剩这条路的20%，这条路全长多少米？
<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">120 / (4/5)</gadget>
<output>150</output>

<result>150</result>