Xiaoqiang's birthday cake has been eaten (3/4), how much is left uneaten.
小强的生日蛋糕被吃了(3/4)，还有多少没有吃．
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>