A glass of pure milk, the first time I drink it (1/3), after filling up with water, I drink it again (1/3), how much milk did I drink in total?
一杯纯牛奶，第一次喝去它的(1/3)，加满水后，又喝去了它的(1/3)，两次共喝了多少牛奶？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(2/3) * (1/3)</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">(2/9) + (1/3)</gadget>
<output>5/9 = around 0.555556</output>

<result>5/9 = around 0.555556</result>