4 tons (1/5) is the same weight as how much (4/5).
4吨的(1/5)与多少的(4/5)是一样重．
<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>

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

<result>1</result>