A rope is 5 meters long, 20% of it is used up, how many meters is used up?
一根绳子长5米，用去了它的20%，用去了多少米．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">5 * (1/5)</gadget>
<output>1</output>

<result>1</result>