20% of a number is 80, what is its (1/2)?
一个数的20%是80，它的(1/2)是多少．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">80 / (1/5)</gadget>
<output>400</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">400 * (1/2)</gadget>
<output>200</output>

<result>200</result>