The ratio of the calf to the elder is 4:5, so how much less the calf is than the elder
小牛和大牛的比是4：5，则小牛比大牛少多少
<gadget id="calculator">5 - 4</gadget>
<output>1</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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