On her birthday, Xiaohong ate a piece of cake (2/8), and her elder brother ate a piece of this cake (3/8). How much of this cake did they eat together? What percentage of the cake did the elder brother eat more than Xiaohong?
过生日时，小红吃了一块蛋糕的(2/8)，哥哥吃了这块蛋糕的(3/8)，他们两人一共吃了这块蛋糕的几分之几？哥哥比小红多吃了这块蛋糕的几分之几？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<result>1/8 = around 0.125</result>