There are 2011 liters of kerosene. The first time we used it, the second time we used the rest, the third time we used the rest, and so on, until 2010 we used the rest There are 2011 liters of kerosene. The first time we used it, the second time we used the remaining 1 / 2, the third time we used the remaining 1 / 3, and so on. Until 2010, we used the remaining 1 / 2, and the remaining 1 / 3

There are 2011 liters of kerosene. The first time we used it, the second time we used the rest, the third time we used the rest, and so on, until 2010 we used the rest There are 2011 liters of kerosene. The first time we used it, the second time we used the remaining 1 / 2, the third time we used the remaining 1 / 3, and so on. Until 2010, we used the remaining 1 / 2, and the remaining 1 / 3

It's a good calculation
The first time is 2011 * (1-1 / 2)
The second time left 2011 * (1-1 / 2) * (1-1 / 3)
.
The rest of 2009
The rest of 2010
2011*（1-1/2）*(1-1/3)*(1-1/4)*...*(1-1/2011)=1
The result is one liter left in the end