A piece of floral cloth is 20 meters, after 8 meters are used up, how much of this piece of floral cloth is left
一块花布20米，用去8米后，还剩这块花布的多少
<gadget id="calculator">8 / 20</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>