(4/5) of A number is equal to (1/5) of B number, how much is A number (fraction) of B number
甲数的(4/5)等于乙数的(1/5)，甲数是乙数的多少(分数)
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">(1/5) / (4/5)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>