30 kilograms is less than how much (1/5).
30千克比多少少(1/5)．
<gadget id="calculator">1 / 5</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">30 / (4/5)</gadget>
<output>75/2 = around 37.5</output>

<result>75/2 = around 37.5</result>