A piece of cake, eat its (2/9), how much is left.
一块蛋糕，吃了它的(2/9)，还剩下多少．
<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">1 - (2/9)</gadget>
<output>7/9 = around 0.777778</output>

<result>7/9 = around 0.777778</result>