There are 500 grams of water in two cups, A and B. Pour (1/2) of the water in Cup A into Cup B for the first time, pour (1/3) of the water in Cup B back into Cup A for the second time, and pour (1/3) of the water in Cup A for the third time /4) Pour into cup B, then pour (1/5) of the water in cup B back to cup A for the fourth time, ..., and pour it back and forth 31 times like this, how many grams of water is left in cup A.
甲、乙两个水杯中各有500克水．第一次将甲杯里水的(1/2)倒入乙杯，第二次又将乙杯水里的(1/3)倒回甲杯，第三次将甲杯里水的(1/4)倒入乙杯，第4次又将乙杯里水的(1/5)倒回甲杯，…，照这样来回倒了31次，甲杯里的水还剩多少克．
<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">500 * (1/2)</gadget>
<output>250</output>

<gadget id="calculator">1 + (1/2)</gadget>
<output>3/2 = around 1.5</output>

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

<gadget id="calculator">500 * (3/2) * (1/3)</gadget>
<output>250</output>

<gadget id="calculator">250 + 250</gadget>
<output>500</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">500 * (3/4)</gadget>
<output>375</output>

<gadget id="calculator">1 + (1/4)</gadget>
<output>5/4 = around 1.25</output>

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

<gadget id="calculator">500 * (5/4) * (1/5)</gadget>
<output>125</output>

<gadget id="calculator">375 + 125</gadget>
<output>500</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">1 - (1/30)</gadget>
<output>29/30 = around 0.966667</output>

<gadget id="calculator">500 * (29/30)</gadget>
<output>1_450/3 = around 483.333333</output>

<gadget id="calculator">1 + (1/30)</gadget>
<output>31/30 = around 1.033333</output>

<gadget id="calculator">1 / 31</gadget>
<output>1/31 = around 0.032258</output>

<gadget id="calculator">500 * (31/30) * (1/31)</gadget>
<output>50/3 = around 16.666667</output>

<gadget id="calculator">(1_450/3) + (50/3)</gadget>
<output>500</output>

<gadget id="calculator">1 / 32</gadget>
<output>1/32 = around 0.03125</output>

<gadget id="calculator">1 - (1/32)</gadget>
<output>31/32 = around 0.96875</output>

<gadget id="calculator">500 * (31/32)</gadget>
<output>3_875/8 = around 484.375</output>

<result>3_875/8 = around 484.375</result>