A colored ribbon is 2 meters long, and (2/5) meters are used for packaging, how many meters are left.
一条彩带长2米，打包装用去(2/5)米，还剩多少米．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">2 - (2/5)</gadget>
<output>8/5 = around 1.6</output>

<result>8/5 = around 1.6</result>