(2/5) of 1 kg is equal to ((())/(())) of 2 kg.
1千克的(2/5)和2千克的((())/(()))相等．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) / 2</gadget>
<output>1/5 = around 0.2</output>

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

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