A bag of rice, after eating (1/5) of it, there is still ((())/(())) of this bag of rice.
一袋大米，吃了它的(1/5)，还剩下这袋大米的((())/(()))．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>