The ratio of the number of big cows to small cows is 4:5, which means that there are fewer big cows than small cows.
大牛和小牛的头数比是4：5，表示大牛比小牛少多少．
<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>