How many meters is left after cutting off 1/5 of the length of a rope 5 meters long?
一根长5米的绳子，剪去全长的(1/5)后，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">5 * (4/5)</gadget>
<output>4</output>

<result>4</result>