There is a glass of pure milk, Wang Bing drinks (1/6) cup and fills up the water, then drinks (1/3) cup and fills up the water again. So how many cups of water did Wang Bing add to the cup?
有一杯纯牛奶，王兵喝了(1/6)杯后加满水，然后又喝了(1/3)杯后又加满水．那么王兵一共向杯中加的水是多少杯．
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

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

<gadget id="calculator">(1/6) + (1/3)</gadget>
<output>1/2 = around 0.5</output>

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