Just after playing basketball, Dongdong felt very thirsty, so he picked up a large bottle of mineral water and drank wildly. He drank half of the whole bottle of water in the first sip, the rest (1/3) in the second sip, 1/4 in the third sip, and the rest in the fourth sip. (1/5), and drank the rest (1/6) in the fifth sip. At this time, there is 0.5 liter of mineral water left in the bottle, so how many liters of mineral water were in the bottle at the beginning?
刚打完篮球，冬冬觉得非常渴，就拿起一大瓶矿泉水狂喝．他第一口就喝了整瓶水的一半，第二口又喝了剩下的(1/3)，第三口则喝了剩下的(1/4)，第四口再喝剩下的(1/5)，第五口喝了剩下的(1/6)．此时瓶子里还剩0.5升矿泉水，那么最开始瓶子里有几升矿泉水？
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/6)</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">0.5 / (5/6) / (4/5) / (3/4)</gadget>
<output>1</output>

<gadget id="calculator">0.5 / (5/6) / (4/5) / (3/4) / 3</gadget>
<output>0.333333</output>

<gadget id="calculator">1 - 0.333333</gadget>
<output>0.666667</output>

<gadget id="calculator">0.5 / (5/6) / (4/5) / (3/4) / 2</gadget>
<output>0.5</output>

<gadget id="calculator">1 - 0.5</gadget>
<output>0.5</output>

<gadget id="calculator">0.5 / (5/6) / (4/5) / (3/4) / 0.666667 / 0.5</gadget>
<output>2.999999</output>

<result>2.999999</result>