After 10% of 10 liters of water is used up, the remaining 10% is added, how many liters of water are there at this time?
10升水用去10%后，又增加剩下的10%，这时有水多少升．
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 + (1/10)</gadget>
<output>11/10 = around 1.1</output>

<gadget id="calculator">10 * (9/10) * (11/10)</gadget>
<output>99/10 = around 9.9</output>

<result>99/10 = around 9.9</result>