A is 20% less than B, B is 25% more than C, how much is A equal to C
甲比乙少20%，乙比丙多25%，甲是丙的多少
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

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

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

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

<result>1</result>