After 4 kilograms increase by 25%, then decrease by 25%, how many kilograms is it now?
4千克增加25%后，再减少25%，现在是多少千克．
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 + (1/4)</gadget>
<output>5/4 = around 1.25</output>

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

<gadget id="calculator">4 * (5/4) * (3/4)</gadget>
<output>15/4 = around 3.75</output>

<result>15/4 = around 3.75</result>