A cup of drink, Xiao Ming drank (1/4) of it, and left ((())/(())) unfinished.
一杯饮料，小明喝了它的(1/4)，还剩下((())/(()))没喝完．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

<result>3/4 = around 0.75</result>