glass of pure milk, Xiaoxiao drank (1/5) and then filled up the water, and then drank (1/3) and then filled up the water again, so how much water did Xiaoxiao add to the glass in total?
一杯纯牛奶，笑笑喝了(1/5)后加满水，然后又喝了(1/3)后又加满水，那么笑笑一共向杯中加的水是多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/5) + (1/3)</gadget>
<output>8/15 = around 0.533333</output>

<result>8/15 = around 0.533333</result>