Xiao Ming's father divides a large cake into 8 pieces on average, mother eats 2 pieces, father eats 1 piece, and Xiao Ming eats the rest. What fraction of the cake does Xiao Ming eat?
小明的爸爸把一块大蛋糕平均分成8块，妈妈吃了2块，爸爸吃了1块，剩下的全部被小明吃完了，小明吃了这块蛋糕的几分之几？
<gadget id="calculator">2 / 8</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 - (1/4) - (1/8)</gadget>
<output>5/8 = around 0.625</output>

<result>5/8 = around 0.625</result>