Xiaoliang ate (1/5) of a box of cakes, and father ate (2/5) of this box of cakes. How much of this box of cakes did they eat together?
小亮吃了一盒蛋糕的(1/5)，爸爸吃了这盒蛋糕的(2/5)，两人一共吃了这盒蛋糕的几分之几？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(1/5) + (2/5)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>