25% of 4 kg plus 4 kg equals 4 kg
4千克的25%加上4千克，等于4千克的多少
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">1 + 4</gadget>
<output>5</output>

<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<result>5/4 = around 1.25</result>