A cake is divided into 9 pieces on average, grandpa eats 3 pieces, grandma eats 2 pieces, and Xiao Ming eats the rest. How much of this cake did Xiao Ming eat?
一个蛋糕平均分成9块，爷爷吃了3块，奶奶吃了2块，剩下的小明吃．小明吃了这个蛋糕的几分之几？
<gadget id="calculator">9 - 3 - 2</gadget>
<output>4</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

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