The fractional unit of (4/5) is the reciprocal of (4/5).
(4/5)的分数单位是(4/5)的倒数的多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">(1/5) / (5/4)</gadget>
<output>4/25 = around 0.16</output>

<result>4/25 = around 0.16</result>