A glass of water, drink half of it for the first time, and then make up for what you drank (1/2), drink half of what you have for the second time, and then make up for what you drank this time (1/2). In this way, after the fifth filling, the water in the cup is the original amount.
一杯水，第一次喝去它的一半，然后补上喝去的(1/2)，第二次喝去现有的一半，然后又补上这次喝去的(1/2)，照这样，第五次补完后，杯内的水是原来的多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

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

<gadget id="calculator">1 * (1/2) * (1/2)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/2) + (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(3/4) * (1/2)</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(3/4) * (1/2) * (1/2)</gadget>
<output>3/16 = around 0.1875</output>

<gadget id="calculator">(3/8) + (3/16)</gadget>
<output>9/16 = around 0.5625</output>

<gadget id="calculator">(3/2) * (3/2) * (3/2) * (9/16) * (1/2) * (1/2) * (1/2)</gadget>
<output>243/1_024 = around 0.237305</output>

<result>243/1_024 = around 0.237305</result>