The ratio of chickens to ducks is 4:5, how much less chickens than ducks
鸡与鸭的只数比是4﹕5，则鸡比鸭少多少
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>