Divide 1 by the reciprocal of (4/5) to get how much.
用(4/5)的倒数去除1得多少．
<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">1 / (5/4)</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>