10 meters long rope, cut off (1/5), how many meters are left.
10米长的绳子，剪去它的(1/5)，还剩下多少米．
<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>

<gadget id="calculator">10 * (4/5)</gadget>
<output>8</output>

<result>8</result>