Mother and father each ate (3/8) of this cake, and Xiaoqing ate (1/8) of this cake. What fraction of the cake did they eat altogether?
妈妈和爸爸各吃了这个蛋糕的(3/8)，小青吃了这个蛋糕的(1/8)．他们一共吃了这蛋糕的几分之几？
<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

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

<gadget id="calculator">(3/8) + (1/8)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>