A cake, Xiaoming ate it (2/7), father ate more of this cake than Xiaoming (1/7), what percentage of this cake did father and Xiaoming eat together?
一个蛋糕，小明吃了它的(2/7)，爸爸比小明多吃了这个蛋糕的(1/7)，爸爸和小明一共吃了这个蛋糕的几分之几？
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(2/7) + (1/7) + (2/7)</gadget>
<output>5/7 = around 0.714286</output>

<result>5/7 = around 0.714286</result>