Mom divides a birthday cake into 9 pieces on average, dad eats 3 pieces, mother eats 2 pieces, what fraction of the cake is left?
妈妈把一个生日蛋糕平均分成9块，爸爸吃了3块，妈妈吃了2块，还剩还剩这个蛋糕的几分之几？
<gadget id="calculator">3 / 9</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">1 - (1/3) - (2/9)</gadget>
<output>4/9 = around 0.444444</output>

<result>4/9 = around 0.444444</result>