25% of a number is 125, what is 50% of it.
一个数的25%是125，它的50%是多少．
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">125 / (1/4)</gadget>
<output>500</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">500 * (1/2)</gadget>
<output>250</output>

<result>250</result>