The number A is 20% more than the number B, and the number C is 20% less than the number A, then the number C is the number B.
甲数比乙数多20%，丙数比甲数少20%，则丙数是乙数的多少．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

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

<gadget id="calculator">(6/5) * (4/5)</gadget>
<output>24/25 = around 0.96</output>

<result>24/25 = around 0.96</result>