Two containers, A filled with a glass of water, B is empty. For the first time, pour the water from A to B (1/2), the second time, pour the water from B to A (1/3), and the third time, pour the water from A to B (1/4)... After pouring it 101 times like this, how much water is there in A?
两个容器，甲装了一杯水，乙是空的．第一次把甲的水倒给乙(1/2)，第二次把乙中的水倒给甲(1/3)，第三次把甲中的水倒给乙(1/4)…照这样倒101次后，甲中有水多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<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">(1/2) * (2/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/2) * (1/3)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/2) + (1/6)</gadget>
<output>2/3 = around 0.666667</output>

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

<gadget id="calculator">(2/3) * (1/4)</gadget>
<output>1/6 = around 0.166667</output>

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

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