There is a cake, Xiaomei and Xiaoqiang each ate it (2/9), how much of the cake is left?
有一个蛋糕，小美和小强各吃了(2/9)，还剩蛋糕的几分之几？
<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">(2/9) + (2/9)</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">1 - (4/9)</gadget>
<output>5/9 = around 0.555556</output>

<result>5/9 = around 0.555556</result>