A carton of milk (1/4) liter, drink (1/8), left ((())/(())).
一盒牛奶(1/4)升，喝掉(1/8)，还剩((())/(()))．
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 - (1/8)</gadget>
<output>7/8 = around 0.875</output>

<result>7/8 = around 0.875</result>