There are two piles of sand, the first pile is 25% heavier than the second pile, how much is the second pile lighter than the first pile
有两堆沙，第一堆比第二堆重25%，那么第二堆比第一堆轻多少
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 + (1/4)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">(1/4) / (5/4)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>