A rope is 30 meters long, cut off (3/5), how many meters to cut off.
一绳子长30米，剪去(3/5)，剪去多少米．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">30 * (3/5)</gadget>
<output>18</output>

<result>18</result>