If number A is (4/5) of number B, then how much more number B is than number A (expressed as a percentage).
若甲数是乙数的(4/5)，则乙数比甲数多的多少(用百分数表示)．
<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>

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

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