20 kilograms is 25% less than how many kilograms.
20千克比多少千克少25%．
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">20 / (3/4)</gadget>
<output>80/3 = around 26.666667</output>

<result>80/3 = around 26.666667</result>